Archive of Our Own ^beta

It should be noted that the Stone World wasn’t exactly a paradise for transgender people.

Which wasn’t unexpected, for Gen. Or for anyone with common sense, he supposed, but acute awareness of how distress can exacerbate existing social tension was the first thing on Gen’s mind after surveying the situation in the Empire of Might. With the scramble for survival, Tsukasa’s obsession with living “as nature intended”, and the… less-than-progressive meatheads that had been chosen to be revived, anyone with a functioning historical memory could see that the Empire of Might was a hotbed for social backsliding. Hell, it was a testament to social backsliding.

The Stone World wasn’t great for many groups of people, actually.

Unfortunately, being transgender meant that there were more… immediate material concerns, as well.

Namely, the fact that Gen had been on either birth control or testosterone from the age of fifteen. Unfortunately, both were now unavailable to him. Along with ibuprofen, chocolate, and vibrators, for the time being.

Yes. On top of dealing with the complete downfall of human civilization, war with a traumatized one-man army, and now some very alarming alien bullshit, Gen also quietly dealt with the return of a hellish monthly cycle.

If he hadn’t already suffered more than any other human being on Earth (while being incredibly brave about it, might he add), this whole unfortunate situation resulted in him being walked in on with three fingers buried inside him, by none other than the man he’d been in love with for years.

Senkuu froze in the doorway of the sonar room high above the deck of the Perseus, gripping a fistful of blueprints unnaturally tight. His eyes, unfortunately, locked onto Gen’s downstairs dilemma. It was just after two in the morning, but the moon above the open ocean provided more than enough light for Senkuu to see what was happening.

He blinked a second later, brain seeming to reboot, and immediately turned to shut and lock the door. His back remained turned to Gen for an uncomfortably long length of time, giving Gen a chance to cover up. Even with his haori draped over his lap he still felt far too exposed.

Senkuu turned around, slowly, his eyes remaining closed for an extra few seconds just in case. Even through the embarrassment, Gen could feel a little sliver of happiness at Senkuu’s care. “Alright,” Senkuu started. “What… what’s happening.” Gen could’ve laughed if he wasn’t being swallowed by shame right now. He tried anyway, to relieve the tension.

“Whew, this is awkward!” Gen’s chuckle sounded hollow even to his own ears. “Just not enough space for some private time on a ship, huh? What’s a guy gotta do to get his own quarters on this thing?”

Gen didn't have to use his mentalism skills to understand that Senkuu wasn’t buying it. The scientist raised an eyebrow, his expression flat.

“W-well, I was actually waiting for someone, so if you don’t mind, Senkuu-chan—“

“No you weren’t, mentalist,” Senkuu sighed. “If something’s wrong, you can ask for help, you know. Our resources are more limited here, but you don’t have to resort to this.”

What Gen was aiming for was breezy and dismissive, but in reality his laugh came out breathless and frantic and incriminatingly clipped. Another wave of nausea and pain seeped out from his lower stomach, burning all the way down to his mid-thighs. He needed out, his more base instincts urging him to go find a hole to curl up and/or die in. “Help? I’m helping myself just fine, clearly! I assure you, Senkuu-chan, I’m not so delicate that you need to monitor my masturbation habits—“

“Gen.” Senkuu cut him off, fixing the other man with a direct look. “You’re bleeding. I know we didn’t pack enough of the villagers’ herbal cramp aide. If it’s bad enough that you’re being this risky, it’s bad enough to ask for help.”

The space that Gen’s reply was supposed to fill came and went. Senkuu watched patiently while Gen, for maybe the first time in his life, couldn't seem to form a solid retort.

It was like he could feel the pain dulling his senses. After a long day of work on the ship in the heat with Ginro and Magma’s incessant arguing that he was expected to solve, Ryusui’s stupid, infuriating laugh ringing in Gen’s ears, all the while this fucking organ that he didn't even want just gnawed at him, and now this — the shame and exposure and Senkuu's genuine concern — the last of Gen’s composure abandoned him.

“I can’t just— just drag you away from—“ Gen finally stammered, when suddenly, to his horror, a tear slid down his right cheek.

Then another. And another. A complete and utter betrayal from his body.

“Shit—“ Gen hissed, instinctively raising his hand to swipe them away, but stopping short. His fingers were still covered in his own blood. “Fuck—!”

“Here.” Senkuu’s voice came from right in front of Gen, making the mentalist jump. He produced a rag from— from somewhere, Gen didn’t see, and gently dabbed at the tear tracks. Then, he uncorked the bottle of water that was slung from his tool belt, wetting the rag before handing it to Gen. He accepted it gingerly.

“Sorry,” Gen muttered, eyes averted as he wiped away his shame. As if his body hadn’t had enough outbursts already, his diaphragm spasmed enough to produce a shamefully loud hiccup. Dammit.

“Nothing to be sorry for,” Senkuu replied from beside him. 

Gen frowned and finally looked over at the younger man. “This isn’t okay, Senkuu-chan, of course there’s something to be sorry for.”

“I’m sorry I barged in.”

“No, that’s not what I meant! You couldn’t have known, Senkuu-chan. I thought Ukyo-chan had the only set of keys—“

Senkuu cut him off. “Sorry I didn’t notice that you were in pain earlier.”

“I hid it on purpose! And it’s not like I’m dying, it’ll pass eventually—“

“I don't care that it'll pass, stop hiding things when I can help you!” Senkuu interrupted again, his volume rising sharply. “I could've seen if we have any other natural painkillers on board or made you a heating pad, or at least gave you different jobs. I'm sure Francois could supplement your meals a little too if you let them know—” The scientist paused, his mouth clamping shut, like he suddenly remembered something. “It's… up to you, though. If this works, I can leave and let you handle it your way.”

Gen laughed, so engulfed in shame that it was all starting to seem funny to him. “Don’t bother. Not like it was working anyway.”

Oops. “I mean—“

“Not working how? Is there something you need?” Senkuu fixed the mentalist with that earnest gaze again, the compassion once again almost too much for Gen’s heart to handle.

“It works, I just- my fingers aren’t— enough." Gen swallowed, the words tumbling from his lips before he could stop them.

He could practically see the gears turning in Senkuu’s mind. What kind of weird pervert’s fanfiction setup had Gen found himself in?!

Despite being on a ship with so many other people, total silence hung in the air between them for several painfully long seconds. He could hear the rush of blood in his ears, feel cramps pulsing through his abdomen once more.

“Do… you want help with that?” Senkuu peeked at him tentatively.

“Senkuu, you can’t mean that.”

“Why not?”

“What about the mess?” Gen met his gaze directly, challenging.

“You brought towels,” Senkuu gestured to Gen’s supplies. Because of course Gen had come prepared for the mess.

“And what about you? Doesn’t the thought disgust you?”

Senkuu had the gall to look offended at this. “What? Why would I be disgusted?”

“Why— you— it’s my period blood, Senkuu! It’s gross!”

“I won’t get sick from touching it. It’s not gross, it’s just part of the human body,” Senkuu shot back. “It’s well known that orgasms can relieve menstrual cramps, because the uterus contracts during orgasm, which acts as—”

And then he was off, listing all the physical benefits one could receive from sex without an ounce of shame or hesitation. And everything he said was completely accurate, like always. God, Gen should’ve seen this response coming from miles away. Anyone could’ve expected Senkuu to take a completely factual approach to this, objectively weighing the risks and benefits and coming to the conclusion that this was simply the most efficient approach to this problem at the moment.

Of course this was a completely emotionally-detached decision for Senkuu.

“—and like you were telling Chrome literally last week, most people just thought it was gross because they had weird, misinformed ideas about sex and uteruses.” Senkuu finished, slightly out of breath from his rant. He had the same look on his face as he did when wanted Gen’s perspective after finally laying out a plan he’d been working on.

That was when it dawned on Gen that Senkuu really, truly, had no issue with this.

Maybe it was a lifetime of being surrounded by people who expected him to be nothing more than a convenient, self-maintaining doll, but it never even occurred to Gen to involve his partners at all with this area of his life. Most of his periods in the old world had been spent hidden away in his room as much as possible, hazy from whatever painkillers his managers had on hand and clutching a heating pad.

As best he could, Gen limited the amount of exposure to his weird body that others had to endure. The sheer disgust and discomfort would completely destroy any semblance of the facade he had painstakingly built for himself. There was no way he could expect things to be the same with someone after they saw how truly freakish the Asagiri Gen that they had come to expect could be—

Ah. The train of thought halted abruptly. There was… a chance that he had some ideas filed away in his mind that he should sort through in his downtime.

But… Senkuu wasn't a partner of his. Not romantically, not sexually. There were times that Gen thought he could see a glimmer of attraction in the way thay Senkuu looked at him, but it was so fleeting and too stupid to bother getting his hopes up over that he had dismissed the possibility entirely.

Maybe Senkuu was willing to do this as a friend, or as a leader? This was just a Senkuu kind of thing to do. He'd probably do it for anyone if they were in Gen's position. It meant nothing.

To Gen, though, it would mean everything.

Could he really continue on as normal after tonight if Senkuu actually touched him?

Can you really continue on as normal as it is?

…yes. He would have to, no matter what. This was all clearly just a matter of efficiency to Senkuu — which was fine. He should be grateful for it, take the chance to get it out of his system. Maybe Gen could indulge in his own silly feelings privately, but none of this would ever — could ever — get in the way of his role of pushing Senkuu and his dreams forward.

“If you're truly offering, I… would appreciate it. Some help.” Gen’s voice was small when it finally broke the silence. He couldn’t bring himself to meet Senkuu’s eyes. “I have lots of my own water and rags too, so you should be able to get clean immediately after.”

“Okay. I don’t really care much about that, I’ve done lots of actual gross stuff in the pursuit of science, so I’d like to think I can handle menstruation like a big boy,” Senkuu smirked, already starting to unwrap the cloth strips around his wrists. His calm, steady composure, his certainty, and God, those strong, calloused hands unraveling the cloth with practiced precision — for some reason, Gen felt like he was getting a strip tease. Another warmth, pleasurable instead of painful, bloomed in his gut.

“Do you know how to do this?” Gen asked hesitantly. Senkuu had likely never had any sexual experiences before even with more typical anatomy, so the thought of this being his first did kind of made Gen’s head spin.

Senkuu just shrugged, putting the wraps to the side and settling himself right in front of Gen. “I got really into learning about reproductive systems once people around me started hitting puberty. Wanted to be informed about what was going on, with everyone.”

It wasn’t even close to a sufficient answer. “Senkuu-chan, knowing how puberty and menstruation work doesn’t necessarily prepare you to do… this.”

Unexpectedly, a Senkuu’s cheeks took on a lovely flush. Even the tips of his ears reddened slightly. “I did a lot of research. Just… trust me?”

Now Gen could feel it in his own cheeks, overcome with a dizzying reminder of why he liked Senkuu so much in the first place. There had never been anyone else that Gen had truly trusted to take care of him so completely. Not a single damn person, alive or petrified or dead. Not with his finances, not with his life, and certainly never with something this intimate.

And yet.

Gen meant it from the bottom of his heart when he said he would fall to Hell with Senkuu. He had a feeling from the moment he saw that tree that he would join Senkuu’s side, but the longer he spent around the other boy, the more he saw who Senkuu was at his core. 

Senkuu, who found a thousand little (and big) ways to improve the lives of those around him. 

Senkuu, who willingly took the responsibility for so much onto his own shoulders, despite being so young.

Senkuu, who, behind his snarky remarks and nonchalant nature, was ultimately fueled by curiosity and compassion.

Gen understood now. There was no one else who would handle this situation better. No one else whose hands Gen could settle in, without fear of being crushed.

“Okay,” Gen murmured. “I trust you.”

The smile that Senkuu gave in return was blinding in the moonlit sonar room. Gen almost had to look away.

As Senkuu reached to remove Gen’s haori from where it was draped across his knees, Gen’s hand shot out to clutch the purple fabric. “W-wait, don’t look—!”

Senkuu looked up at the mentalist — no anger in his expression, just confusion. “Mentalist, I’m not going to see anything shameful or gross. It’s just your body. But you can keep that over you if you really want.” He let go of Gen's haori and instead placed his hand on the floor right between Gen's open legs, just inches from him. Senkuu's lips twitched slightly upwards, smug. “I don’t need to see to know what I’m doing.”

Gen felt his cheeks burn. What on Earth gave this nerd the sort of confidence to make such lofty claims?! To look at Gen with such a sultry expression?! There was no way that Senkuu had more than a few experiences with this and even that was a generous estimate, while Gen had years of sexual encounters under his belt. Physically vulnerable though Gen might’ve been, he refused to sit idly by while Senkuu made a puddle of him. 

He raised an eyebrow as he met Senkuu’s gaze. Gen twisted his gaze into something seductive, challenging, as he rose to the occasion. His feet slid further out, allowing the scientist to get even closer. “eally-Ray, Senkuu-chan? Let’s see if you can live up to the high bar you’re setting.”

Senkuu swallowed, and Gen swore he saw the younger man’s eyes flicker down to his lips. He reached his hands underneath the haori, settling on Gen’s inner thighs before inching even closer. He tightened his grip, squeezing the mentalist’s soft, sensitive thighs. “I know I can.”

Traitorously, Gen couldn’t stop his own eyes from glancing at Senkuu’s lips. They were so close, practically sharing breath, and the scientist’s scarlet eyes felt hypnotic.

“Kiss me, Senkuu?” Gen whispered, and Senkuu did.

The first press of Senkuu’s lips against Gen’s was so soft, so hesitant, that Gen wasn’t entirely sure it hadn’t been a hallucination. If he wanted to, Gen could just snatch control away from Senkuu right now — grab him by the collar and crash their lips together, pull him into a heated kiss before telling Senkuu exactly how he wanted to be touched, and Senkuu would let him.

But now… now he was curious. Gen had been in love with Senkuu for years, he had considered what sex between them might look like, if it ever happened. He imagined Senkuu to be cautious of sex, maybe uninterested entirely, and Gen had prepared himself for that. He'd long since accepted that he would follow Senkuu wherever he led, no matter the nature of their relationship.

This, though… this confidence was unexpected. Senkuu had taken charge so easily, and Gen couldn’t deny that he wanted to follow to see where it went.

Maybe he needed the slightest nudge, though.

Gen parted his lips slightly and pressed with more insistence against Senkuu, who obliged with the subtle demand easily. His lips fully slotted against Gen’s, moving in sync now with each other, like he had done this all before. He breathed in through his nose, sighing contentedly against Gen’s cheek. They were impossibly close now, the mentalist’s back pressed against the wall and Senkuu’s legs acting as supports, wedged beneath Gen’s thighs. He slowly moved his hand from where it had been rubbing circles into Gen’s inner thigh, to the curve of his lower stomach, where he pressed the heel of his palm in slowly but firmly, gently massaging the region where Gen’s uterus was.

It was Gen’s turn now to let out a sigh. This actually felt… really nice. Not enough to completely soothe the pain, of course, but Senkuu’s warm hand pressing into his sore, contracting muscles was definitely an improvement.

And then, Senkuu decided to kick it up a notch. Several notches. The mentalist barely registered Senkuu’s other hand moving inward from Gen’s thigh before Senkuu's hand was cupping his pussy, squeezing his clit between the base of his fingers. It was exploratory, mapping this part of Gen in his mind.

After just a few seconds, Senkuu had apparently familiarized himself enough with Gen's body, because suddenly he was pressing two fingers into him and curling them upward. Gen moaned openly into the scientist's mouth, unable to contain himself from the surprise and the sensations. He could feel Senkuu smirk into their next kiss, the smug bastard.

And then, Senkuu began to move his fingers. 

Slowly at first — just massaging the sensitive, spongy space with the rough pads of his fingertips. Gen exhaled, the end of his breath morphing into a moan, as Senkuu pressed insistently inside him. They broke away from their kiss, breaths mingling between them, until Gen's breath caught in his throat as he opened his eyes.

Ruby red burned through him, trapping him. Senkuu, usually distanced from those around him, was focused on Gen, and only Gen. The mentalist had a way of slipping through people's fingers, but the way Senkuu's gaze held him down like a moth on a pinboard — there was no escaping that.

Gen trembled as Senkuu picked up his pace, his fingers fully fucking into him and still hitting that damn spot. What little attention that Gen was able to rip away from the nerves Senkuu was hitting was able to register the wet noises that Senkuu was creating with his body, the perverse sounds filling the otherwise silent room.

"Fuck," Gen panted, his gaze turning hazy against Senkuu's stare. In all his years in the spotlight, he had never felt more like he was under a microscope until now. Probably because there was a good chance that Senkuu was treating this like an experiment of sorts in his head. Internally categorizing every huff and moan that left Gen's lips in an attempt to build a working model of this side of Gen.

And fuck, it was working. Every second that passed only exposed more of the mentalist. Senkuu only gained more confidence as he continued, picking up on the skill of pleasuring Gen exponentially.

It should've been unnerving, instinctively distressing to someone like himself. Someone who had fought tooth and nail his whole life to never truly be unraveled.

But if anyone was going to solve him, to map Gen's uncharted waters, it was going to be Senkuu.

At that moment, Senkuu thumbed at Gen's clit, sending a fresh jolt of pleasure through Gen's body. The moan that left Gen's lips was embarrassingly real, stilted and cracking as Senkuu introduced an entirely new dimension of pleasure to this. Senkuu tried a few different movements, the pad of his thumb rubbing Gen's plump little cock with a slight awkwardness, before he settled on hard, slow circles.

Once he got the individual components down, Senkuu's movements were methodical, like a well-oiled machine. He hit Gen's G-spot every time his fingers fucked into him, his thumb circling Gen's clit rhythmically with each movement. It felt like Senkuu's fingers were coaxing an orgasm out of Gen from every angle, inside and out. He let out a shuddering groan, thighs tensing around Senkuu's torso.

"That's it," Senkuu murmured, breath hot in Gen's ear. "Gotta let me know when it feels good."

It was so surreal, it was almost dream-like. The pain he'd been in before was nothing but a memory at the edge of his awareness, pushed back by waves of warm pleasure buzzing deep in his core. How was this even happening…?

Gen only registered his head tipping back when he felt it hit the wall. His eyes were only half-lidded, expression dazed. "Sssen— kuu-cha—an—"

"Gonna cum?" Senkuu asked, even though Gen was sure he already knew the answer. His face was buried in Gen's neck, canines scraping the thin skin lightly. With all the strength he could muster, Gen nodded, his breaths coming out shaped like the word 'please'.

The scientist chuckled in response, his pace quickening again. The little breathy moans escaping from Gen's lips morphed into curses and begging, his hands clutching at Senkuu's clothes and hair frantically.

Senkuu carefully observed all of it. Felt the way that Gen's inner walls tightened around his fingers, felt his little cock twitch under the meat of his thumb. By now, the mentalist's cheeks, ears, and neck had become completely flushed. His mouth hung open, tears gathering at the corners of his eyes.

Senkuu's forearms were beginning to burn with exertion. He could feel his muscles getting tired, his breath coming quicker and quicker. He was certain that he'd never been so hard in his fucking life.

"F-fuck, Sen—kuu-ch— ah, I'm gonna—" was all Gen managed to get out before Senkuu felt a gush of warmth around his fingers. A string of whimpering moans spilled from Gen's lips, his grip on Senkuu's hair turning pleasantly painful.

The mentalist continued to fuck himself through his orgasm on Senkuu's fingers, grinding his hips against Senkuu's hand shamelessly. After a minute, Senkuu could feel the other man's muscles relax as the aftershocks of his orgasm receded, and reluctantly pulled his fingers out. He wiped them off immediately as Gen had mentioned earlier, if only so Gen wouldn't get embarrassed.

(He knew most people would think it was gross, but if Senkuu was going to be extraordinarily honest, all of this was strangely sexy to him. Even putting aside the inherently exciting aspect of intimacy and vulnerability in Gen allowing him to be involved in something that he typically kept hidden away from the world. The heady, coppery smell of blood and sex in the air, the abundance of warm liquid running down his fingers, the fact that all of this was because of Gen's reproductive processes, combined with the use of Senkuu's own knowledge of biology — people could call him a freak as much as they wanted, but Senkuu was not one to deny his own interests.)

"Satisfied, mentalist?" Senkuu asked, not bothering to keep the grin off his face.

Gen cracked one eye open, the corners of his lips already creeping upward, mirroring his friend. "'Satisfied' is a bit of a foreign concept to me right now, but my cramps are efinitely-day one-gay for now."

One of the scientist's eyebrows quirked upward, curiosity piqued once again. "Want more?"

Gen laughed, waving his hands around nervously. "Th-that's quite alright, Senkuu-chan! It's late anyway, and I'm sure you have more pleasant things to do than deal with me and my biohazards. You've already helped me out more than enough." He knew that as eager to help as Senkuu was, physical contact — especially sexual contact — were not typically things that Senkuu enjoyed. Guilt was already lapping at Gen's stomach; he wanted to give Senkuu as many outs as possible.

In response, Senkuu was quiet for a long moment, his jaw tensing like it did when he was debating whether or not to say something. Eventually, he met Gen's eyes again with an uncharacteristically uncertain look. "Listen, I'm going to be honest — that was probably the hottest thing that I've ever seen. If you really don't want to then tell me, but if you're just trying to push me away so I don't think you're gross or whatever, you're wasting your time."

Gen felt like he'd had the wind knocked out of him.

Senkuu… was turned on by this?

Even though he heard the words that just left the scientist's lips, knew that Senkuu was unyieldingly honest, he couldn't wrap his head around what Senkuu had said. He decided to chance a painfully obvious glance downwards and saw—

Senkuu really was sporting a raging hard-on. The tent in his weird little science dress was undeniable, and if Gen looked closely — oh, God. A small, dark spot of precum had seeped through to stain the scientist's clothes. Gen couldn't deny the burn of desire that still smoldered between his legs, his dick beginning to pulse to life again.

"Uh, I… haven't made condoms yet, though," Senkuu admitted rather sheepishly. "It's unlikely that you'd get pregnant while menstruating, and I don't have any diseases. If you don't want to chance it I could always use my fingers again though."

"I… was tested shortly before the petrification. I don't have anything either. But…" Gen finally broke their eye contact, unable to will himself to meet Senkuu's gaze any longer. "…are you sure you won't get sick?"

"Sick? Nah," Senkuu replied easily. "I'll just pee afterwards, simple."

Gen squirmed. "But do you really want your first time to be… this? You don't have to take care of me, Senkuu. I'd like to think I can handle menstruation like a big boy," he echoed Senkuu's own words from earlier with a small smile.

Senkuu huffed and returned the smile. "Do you really think I give a shit about something like that? Mentalist," he settled back on his haunches and crossed his arms on Gen's bent knees, inching in close. Senkuu's breath ghosted across Gen's neck and chest. "There's really only one question we need answered. Do you want me to fuck you?"

For what felt like the hundredth time in an hour, Gen's breath caught in his throat. He felt his cunt clench around nothing, squeezing out a glob of liquid that dripped down his crack to join the growing wet spot on the towel underneath him. Fuck, he really, really wanted this.

In a humiliating moment of honesty, he nodded his head desperately.

"Good. I do too," Senkuu said simply. When Gen found the courage to look back at him, Senkuu's gaze burned against his. He licked his lips, the movement drawing Gen's eyes downward.

"I'm going to kiss you again," Senkuu murmured.

"Yes," Gen said breathlessly. "Please."

And Senkuu did. Their lips met in an open-mouthed kiss, tongues slick against each other. The scrape of Senkuu's sharp canine against Gen's tongue was a sensation that went straight to Gen's dick. The mentalist wrapped his arms around Senkuu's neck, pulling him ever closer, until Senkuu's clothed bulge pressed against Gen's exposed cunt. Needy groans erupted from both of them at the sudden contact. If Gen was ever going to get a taste of Heaven, this was it.

…was what he thought, until Senkuu reached down and fiddled with something, and then his bare cock was pressed against Gen, hard and pulsing with arousal. A low noise rumbled out of Senkuu's chest, and Gen's hips automatically canted upward, chasing the friction.

From there, their bodies moved in tandem. The slick slide of their hips together was downright addictive. With every thrust, the ridges of Senkuu's cockhead rubbed into Gen's dick in a way that obliterated any other thought in his mind. The slick sounds were back again as the movements coated Senkuu in more and more of Gen's juices.

There was no telling whose change in position resulted in it — Gen's hips tilting upwards just so, or Senkuu pulling just a touch further back, it was lost on them. But at the next second Senkuu's cock was catching on Gen's hole and sliding easily into the mentalist, pulling gasps of surprise from both of them and breaking their kiss, until the front of Senkuu's thighs were flush against Gen's haunches.

"Oh fuck, Senkuu—" Gen whined, his head tipping back once again. He wasn't too big for Gen, but Senkuu had always walked around with the kind of big dick energy that only a nerdy twink could pull off, and Gen could now feel why. He had felt Senkuu start to nudge up against his cervix more than an inch ago. With the little room he had he began to circle his hips, reveling in the stretch of Senkuu inside him, before a hand on his abdomen stopped him.

"Wait," Senkuu hissed, his eyes screwed shut in concentration. In the hazy dimness of the room, Gen could see a drop of sweat roll down Senkuu's temple and over his cheekbone. The scientist's breaths came out in huffs, strained.

The mentalist felt a pulse of want within him at that. Senkuu had almost cum just now.

Gen was not a patient man. He was selfish, indulgent, eager to sink his teeth into things he truly desired. A fair few treats — food, possessions, people — and Gen's lack of restraint regarding them had landed him in hot water back in the old world.

Casual sex had been his MO in modern times. It was a game, a performance, an experiment in its own right of what Gen could turn himself into for a night. Beyond a sense of accomplishment and control, it didn't do much for him emotionally. Right now, though, it was like he could feel the dopamine and oxytocin rushing through him, every part of his body buzzing with pleasure while completely erasing the days worth of pain and discomfort. Gen could have stayed in this moment for an eternity.

He gingerly slid his hand up to cup Senkuu's cheek. The scientist met his gaze immediately, his eyes flickering with shifting emotion.

Sometime in the last minute, their breathing had synced.

Gen brought their lips together in a firm, passionate kiss once again.

Senkuu's hips began to rock back, testing the waters, before sliding flush with Gen's again. The rhythm he set was steady, each thrust reaching so achingly deep within Gen. The angle had Senkuu dragging repeatedly against all the most sensitive spots within him. Pressure was already building fast in the older boy's gut. He was still so sensitive—

The hand that was still holding Gen's stomach suddenly shifted back down to the same spot from earlier before pressing down.

A low purr of a moan rumbled out of Gen's throat right against Senkuu's lips. The pressure stimulated them both, Senkuu's cock grinding even harder against every inch of Gen's inner walls, which in turn made him grip Senkuu even tighter.

Senkuu's thrusts were turning sloppy in both rhythm and sound. Gen sent a quick prayer out to whoever was listening that Ukyo was wearing his headphones tonight; on top of their slick thighs slapping together with every movement, Gen could hear how wet he was from the obscene sounds of Senkuu fucking into him.

Their free hands grabbed onto whatever they could reach of each other, Gen's hand returning to tangle itself in Senkuu's hair. He'd probably have a bruise shaped like Senkuu's palm across his hip tomorrow.

"Can't last," Senkuu panted, a slight growl in his voice from exertion. "Touch yourself, Gen, ah—"

Gen did as he was told, his fingers flying frantically over his clit. Breathlessly, "Inside me, please, Senkuu, ah— please, cum inside me—"

Gen's orgasm struck him like a bolt of lightning, a jolt of electricity that tightened every muscle in his body. Gush after gush of liquid squirted out of him and down his partner's thighs, a torn, stilted cry ripping out of his throat.

Senkuu bit down on the junction of Gen's neck hard over his still-laced undershirt, mindlessly fucking into the mentalist, before groaning and snapping his hips flush against Gen's one final time. Warmth flooded the deepest part of him, making Gen clench, milking Senkuu through his orgasm.

They immediately slumped together, panting, Senkuu still buried inside Gen. Gen's arms wrapped around Senkuu's neck, holding the other man to his body.

For a minute they didn't move, their lack of both stamina and coherent thoughts turning them into puddles in each other's arms.

Like puppets with their strings cut, Gen's jumbled brain concluded. They were so tangled together that it was hard to tell where Gen ended and Senkuu began. The intimacy of the position set butterflies loose in Gen's stomach, making him clench around the scientist involuntarily.

"Oi," Senkuu patted Gen's side, still slightly breathless. "Don't do that, or we'll never get to bed."

The implication of Senkuu's words already rekindled the warmth low in Gen's gut. "Oh, really, Senkuu-chan?" With his fingertips just underneath Senkuu's chin, he gently tipped the other man's head up to meet his gaze. A little teasing, a sultry look — that might be enough to hide the effect that Senkuu's words had on his heart. "That's all it would take to pique your interest again? Careful, dear, I might end up thinking you like me~"

Even in the dark, at this distance, Gen could clearly see Senkuu's pupils go wide. More damning still, he could feel Senkuu pulse against his sensitive inner walls, his cock beginning to swell inside Gen once more.

Fuck. Gen could feel the flush immediately overtake his cheeks and neck. "S-Senkuu-chan, you dirty dog!"

A matching blush rose just as quickly up to the tips of Senkuu's ears. "I'm a healthy young man, gimme a break!" He buried his face in Gen's chest, the fabric of Gen's many layers muffling words that sounded suspiciously like 'of course I would react to you saying something like that.'

It was cute. Who knew the scientist could get so cuddly? Gen rested his hand on the back of Senkuu's head, patting him a few times and petting his hair. "Thank you, by the way. I feel much etter-bay, my cramps are completely gone. I'll finally be able to get a good night's rest."

Senkuu went still against him for a moment before his arms tightened around Gen's waist. He turned his face inward from the mentalist's chest, tucking his forehead into the crook of Gen's neck. "You don't have to thank me for this. I want to help you when I can."

Gen couldn't help the grimace that pulled his lips down. "This is a little much to ask of someone, though… especially to ask of you."

"Because you didn't think I'd be into it?"

"Basically, yeah," Gen nodded. "Every time someone has come onto you, you've turned them down. Most times you seem pretty disgusted by sex and romance, actually."

He could feel Senkuu frown against his collarbone. "They're definitely not things I seek out or prioritize, but I'm not necessarily… completely uninterested."

Gen hummed. "Still, this sort of situation is definitely a lot to suddenly handle, right? Having it sprung on you out of nowhere, with someone that you're… not like that with."

Senkuu's frowned deepened, then he pulled back entirely, his eyes locked on Gen's. "You didn't spring anything on me. I stayed because I wanted to. I helped because I wanted to. I'm the one that walked in on you jerking off, and I could've walked out whenever."

Gen sighed a genuine sigh of relief. He would've never been able to live with himself if he knew that Senkuu had felt forced into this. The scientist had a tendency to overextend himself when others were depending on him. There was no guarantee that Senkuu would feel the same in a week or a day or an hour, but… whatever damage occurred could probably be repaired.

Silently, Gen thanked whatever deities had saved him from destroying the most meaningful bond he'd ever had, and then patted Senkuu's sweaty hair once again. "Come on, genius. We should get going before we fall asleep here like this."

Senkuu grumbled, but ultimately complied. With hisses from both of them, Senkuu pulled his mostly-flaccid dick out of Gen, a rush of liquid following. Gen shivered at the sensation.

It was partially hidden by the dark room, but it really did look like a murder scene. The towel underneath them along with the square foot of skin around their crotches were all covered in blood, semen, and other body fluids. They both washed their hands and wiped their bodies clean with water and a small chunk of soap before redressing.

Menstrual hygiene tools in the Stone World were definitely not as advanced as they were in the 21st century. However, the tools that the villagers used were effective, while somewhat primitive, and Senkuu's improvements made them much less of a hassle than Gen had worried they would be. He had brought both a pad and a tampon with him in preparation of sleeping after this, which he got in place before putting his clothes back on. He could tell from the way Senkuu's eyes kept flicking over to him that he was debating asking if he could watch Gen put a tampon in (for research or sexual purposes, Gen wasn't entirely sure at this point).

Gen rolled his eyes. Another time, maybe, when he was feeling less gross.

One short bathroom break (which felt more like a stealth mission) later, they began trudging back to their sleeping quarters.

Something began gnawing at Gen.

What… did this all mean for him and Senkuu? How was he supposed to conduct himself around the scientist after this? Would it be rude to just pretend like nothing happened, or was that exactly what Senkuu wanted him to do?

None of Senkuu's actions on the way back swayed Gen either way. He helped Gen carry some of his things and locked the door behind them after they left the sonar room, yawned, stuck his pinkie in his ear… none of this solved Gen's dilemma.

Would Senkuu hate Gen after this? Sure, he was feeling fine after a positively mind-blowing orgasm, but what about once he had time to think about it? Would this be what finally got Senkuu to resent, to despise Gen? To realize that he wasn't being joined in his descent to Hell, but dragged down by a man who he thought was a friend?

The vision of what Gen would be looked back upon as swam in his mind. The manipulative two-faced freak using the younger, eager-to-help scientist to satisfy his own sick desires. Teetering on the brink of destruction due to his own foolish actions… he should start preparing a backup escape plan for whenever they got back to Japan.

Senkuu's hand suddenly grabbing his pulled Gen out of his thoughts. The scientist's calloused fingers sliding to interlock with his own stopped Gen in his tracks.

Gen froze. His mind went blank.

He looked down and found that no, he was not experiencing phantom sensations. There was Senkuu's hand holding his, like it was the most natural thing in the world.

"I can hear you thinking, mentalist," Senkuu said. Gen, still puzzled by what was happening with his hand, didn't look to where Senkuu was almost certainly watching him.

Regardless, Senkuu continued. "We're okay, Gen. Nothing needs to change right now. We'll figure it out a different day, I'm pretty sure our brains have basically stopped working for the night."

Gen studied their interlocked fingers for a few more moments before finally murmuring, "I didn't realize your brain ever stopped working."

A snort from Senkuu finally brought their gazes together. "Guess we found an effective shutdown method." A smile bloomed on Gen's face.

Without exchanging any more words, Senkuu led them both to the sleeping quarters, where nearly every bed was filled with sleeping bodies.

They walked down to where their beds were. Their beds were separate, of course, one row offset and across the aisle from each other. This was where they would leave each other for the night.

Senkuu let go of Gen's hand only to pull back Gen's blankets, dump both of their armfuls of Gen's belongings onto his bed, and cover them with the blankets again.

Gen looked over at Senkuu, confused, but didn't receive even as much as a glance before being tugged in the direction of Senkuu's bed.

Before he had time to even internalize what Senkuu's plan was, he was dressed down and cuddled under the blankets with the scientist, his head tucked into the crook of the other man's neck. Their arms draped over each other's bodies automatically, like they'd been doing it all their lives.

"For what it's worth, I do like you. Idiot." Senkuu exhaled, barely audible, and then he was out.

All Gen could do was be grateful for the cover of darkness and Senkuu's blankets. Safe in the scientist's arms in the middle of the Pacific Ocean, Gen felt a tired, dopey smile tug at his lips before he fell into a blissful dreamless sleep.