Senku’s Dearest

shockingly, senku couldn’t pinpoint exactly where in the timeline the novelty of the relationship became second nature to you both.

distance shortened, literally and figuratively. you talked to him about anything and everything, not that you didn’t before, but senku thought this kind of talk was new. he started to feel swells of pride every time you sought him out for something, from questions about stars to if he would still like you if you were a worm. he liked your attention on him.

he liked your hands on him even more. they were usually casual touches, seemingly friendly to outsiders looking in, but to senku, he wanted to drown himself in it.

it was honestly baffling to him how affected he gets, ears red and skin delightfully warm, when you pat him sweetly on the cheek, run your fingers through the valleys of his knuckles, or press against his back, clinging onto his shoulders in an unexpected hug.

senku found himself reaching for you more too. your hand fitted perfectly into his, and so did your jaw. he grew addicted to the feel of your face in his hands, loved to trace your cheek bones down to the back of your neck, pressing light swirls into your skin.

3700 years into the future, where he becomes quite literally the smartest guy alive on the planet, senku has a multitude of things to think about, food, water, a new lab, if tsukasa really is going to build an army to off one measly scientist, and you. more specifically, the whereabouts of you.

he can’t find you, and that worries him. he knows you weren’t too far away from him before the petrification, exactly one seat from the window, doing some work you had forgotten while he was looking out of the window down at two little lovebirds.

he knows you shouldn’t be far, but he hasn’t found you yet. so, instead of missing your rambles and the delicate pressure of your skin on his, senku tries to focus more on the situation at hand. he thinks of items that would help him, a little bit about the possibility of death and advancing the kingdom of science. after all, he can’t just revive you into a world that’s just barely on its way to crawling. you would not like that.

as all good intelligent organisms do, senku adapts. he begrudgingly gets used to keeping his hands to himself. he misses the warmth of another on him, but it’s nothing an actual fire can’t fix! (spoiler: it doesn’t fix. he still yearns for one of your signature hugs where you squeeze and pepper kisses under his jaw. you’ve ruined the guy.)

he sidesteps away from the overly clingy advances of the others and favours quick interactions.

taiju he can tolerate. he doesn’t mind his hearty slaps on the back or the jigglings of his shoulder. the oaf is his best friend for a reason. yuzuriha’s company is preferred though, when taiju gets too excited. there’s only so much his ears can take. no more of either of them, alas, they’re all the way at camp tsukasa.

chrome is similar when he gets excited about science-‘sorcery’. his enthusiasm bleeds out into large gestures very deep into senku’s personal bubble, but that’s fine. the people of ishigami village are their own characters. he makes it his mission to not collect any more who do not know the definition of personal and space.

the lioness keeps her distance, which senku appreciates. what he doesn’t appreciate is whenever kohaku throws him over her shoulder and chucks him away from the general vicinity whenever he talks about something true. objectively true. not his fault she doesn’t like facts.

gen usually keeps his distance as well, but when it comes to his tricky schemes, gen isn’t below using his boundaries like a skipping rope. whenever he has that silly little gleam in his eyes, senku makes a point in avoiding him and his schemes.

senku finally finds your stone self just a few days after hyoga’s attack on ishigami village.

he’ll be honest, but as soon as he laid eyes on your statue, he almost collapsed to his knees, weak with sheer relief. however, after being hit with pure unadulterated joy, a dash of fear crashes into him.

how is he going to explain all of this to you?

hello lover, sleep well? missed you a bunch. how do you feel about war in a year against the tsukasa empire? what’s the tsukasa empire you ask? long story but basically it’s the strongest primate highschooler plus 100 others. how about we make it a date? you’ll get to see the tank that i’m working on — yes, a tank. it’ll be the first date in 3702-ish years. yes, i look a little worn. no, it’s not your eyes. your boyfriend has just aged a year and a bit without you.

senku can’t really bring himself to care much about it anymore. he’s selfish at heart. he’s taking his shirt off so quickly that he almost defies physics, and grabs the secret vial of revival fluid from his pocket that’s reserved for you and only you.

he hears a squeal from behind him, probably gen, maybe chrome. his vision is tunnelled on you.

it’s been 39,484,800 seconds since he had revived without you. 457 days — a year and three months. he tries to be as gentle as he can when he dresses your stoney body, but he’s desperate. forgive the guy will you?

as the stone falls from your body, senku doesn’t dare to move away from you, to the surprise of the mini audience of three he’s garnered. their reactions to the scene are either ones of loud shock (eyes wide and jaws agape, chrome could catch flies with how wide his mouth is) or excited gossip.

senku tries to angle his body in a way that hides the majority of yourself away from prying eyes. something stupidly close to possessiveness nestles into his chest. you haven’t even fully revived yet and he wants to keep you all to himself.

… so he hasn’t grown out of his clinginess in your absence. just his luck. (not that he would trade that for all the stars in the sky.)

you look confused when you finally manage to crack open your eyes. (valid fucking reaction, he should’ve hauled your statue back to the village and into his room instead of reviving you in the middle of nearly nowhere.) the hoarse sound of his name leaving your lips nearly has him throwing himself at you. he lets out a breath he didn’t know he was holding.

“sleep well?”

“senku, why don’t you have a shirt on?”

back at the village, and after a brief explanation on, well, everything up to now (and finding some more clothes) introductions formally start. gen, chrome and ginro are all too happy to meet you. questions upon questions to which you answer happily.

out of habit, senku sits closer to you, shoulder to shoulder. you lean into his warmth. he finally feels at some sort of peace again by your side.

he knows he should be thinking about other things, science-y solutions to a war with no bloodshed, but his brain is just drowning in a cocktail of oxytocin and the familiar presence of you.

gen opens his wicked mouth, teasing.

“so it seems that dear senku has a lover, is that right?”

before you say anything in response, senku groans a blunt ‘yes’ and moves to rest his head on your lap, arms circling around your waist. instinctively, your hands make their way into his hair, playing with the strands.

all chatter seems to stop.

kohaku is the one to break the silence, “well, that’s the first time senku’s ever touched someone willingly.”

titters of agreement. oh well. all he does is clutch on to you tighter, trying to hide his reddening face away from everyone. you giggle at all their reactions. it’s a quiet sound but there all the same. god, he can’t think straight.

the next day, the day after that and the weeks after those, senku seems to have superglued himself to your side. the village slowly gets used to their new leader and his beloved/“betrothed”/lover.

gen truly laments the loss of smartphones and cameras. the number times he’s caught the two of you snuggled asleep together is astounding. senku never seems to leave you. always an arm around your waist, or a hand here or there. you don’t mind, used to the physicality of senku, of being practically joint at the hip.

hey so hi! i have been quite busy these past few days with school, so i hope you guys enjoy this!!! not fully proof read im so sorry if it’s a little well shit but yahhhhhhhhhhhh my brain was about to melt when i was figuring out the timeline and the aging aspect of this … probs was not that deep but eh i managed to map it out lol thank you anon for req 🫶🫶🫶

Usually this happens after months of continuous focus.

Three or four months is not unrealistic. Senku is the type of person who can bury himself in his work so completely that his own body becomes secondary. Hunger, fatigue, and physical discomfort are already things he routinely pushes aside. Sexual tension falls into the same category—another biological process to be tolerated until it starts interfering with his ability to think clearly.

When that point arrives, the decision becomes purely practical.

A factory reset for his brain.

It almost always happens late at night.

Senku is lying on his back staring at the ceiling, mind moving too fast for sleep to catch up with it. Ideas keep colliding with each other—unfinished formulas, chemical ratios, plans for the next day...

But beneath all of that there is a persistent physical tension he can’t ignore anymore.

Once he acknowledges it, the conclusion is immediate.

Deal with it quickly. Go to sleep. Return to work.

He doesn’t romanticize the act at all. There is no ceremony to it, no drawn-out anticipation. One hand slips under the blanket and wraps around his cock with the same detached focus he would apply to adjusting a piece of equipment. His grip is firm but impatient, strokes short and functional because the goal is simply to finish as quickly as possible.

Efficiency governs everything he does, even here.

At first the only indication of what he’s doing is the subtle shift in his breathing. Slow inhales turning slightly heavier. His jaw tightens. His brows pull together in concentration. Sweat eventually gathers along his temple, damp strands of hair sticking against his forehead as his body gradually reacts to the stimulation.

He's not all too vocal.

Occasionally a soft grunt escapes him, or a muttered curse when his hips twitch involuntarily into his hand. But he’s careful. The last thing he wants is someone waking up and asking questions he has absolutely no interest in answering.

The closer he gets, the more his initial mechanical rhythm gives way to urgency.

His strokes grow faster. Less controlled. His breathing breaks into uneven bursts as the pressure in his abdomen tightens. His body responds before his mind fully catches up, muscles tensing as the sensation builds rapidly toward release.

When he cums, it hits him all at once.

Afterward he lies still, staring up at the ceiling while he catches his breath. His mind goes blank for a moment, like everything inside his head has finally gone quiet. His cock still twitches faintly in his hand, sensitive and warm, but the tension that had been building in his body is gone now. What’s left behind is a heavy, relaxed tranquility.

He gives himself a minute, maybe two, before cleaning himself up and moving on with whatever he was doing before. Most of the time, that’s the end of it.

But things change slightly once someone starts occupying his thoughts.

The difference is subtle. He still ignores the urge most of the time. He still treats the act as something purely functional when he finally gives in to it. Yet once there is a specific person attached to those impulses, the situation becomes more complicated in ways he does not particularly appreciate.

Your image starts appearing in his mind at the most inconvenient times.

What used to be something he did purely to kill the urge slowly shifts into something else entirely. Something he actually enjoys. And the first time he realizes that difference, it throws him off more than he'd like to admit.

He finishes harder—faster.

And afterward he just sits there for a moment, staring down at his own hand like he’s trying to analyze what exactly just happened.

He knows what happened, of course.

He just doesn’t like the implications.

Because once that connection is made—once his brain links that feeling to you—it becomes difficult to separate the two again.

And despite himself, he gets hooked on it.

You become the muse for his decidedly unscientific desires.

The first time he takes your panties, he genuinely doesn’t mean to.

It’s one of those impulses you act on without thinking, only realizing what you’ve done a second too late. The kind of mistake that immediately makes you go: I probably shouldn’t have done that.

But by that point it’s already too awkward to undo.

Returning them would raise questions. Keeping them feels just as questionable. And somehow the situation becomes worse the longer he stands there holding them.

So he keeps them.

At first he tells himself it was just a lapse in judgment.

But when the moment comes later—when he’s alone, tense, and the familiar pressure has started building again—he realizes he doesn’t regret taking them nearly as much as he thought he would.

The fabric ends up wrapped around his cock before he can really think about what he’s doing.

His hand closes over both at once, fingers tightening as he gives an experimental stroke. The material drags differently against him, softer, thinner, and the sensation makes his hips twitch forward instinctively.

He exhales sharply.

Then his hips start moving.

Slow at first, testing the friction as he thrusts into his own grip, the panties twisted around his cock while his hand works over them. It doesn’t take long before the image slips into his mind—of you instead. Your body wrapped around him, your warmth, the way your pussy would squeeze him every time he pushed forward.

The thought makes him far more sensitive than usual.

His rhythm falls apart almost immediately.

His hips start thrusting erratically, short uneven motions as he fucks into his own fist, trying to keep quiet while small whimpers and breathy sounds slip past his lips anyway. His grip tightens around himself, cock twitching hard every time his mind drifts back to the thought of you.

Feeling your panties wrapped around him quickly becomes one of his favorite sensations.

But that isn’t the only thing he does with them.

Sometimes he presses them against his face instead. He buries his nose right against the gusset of the worn fabric, inhaling deeply while his other hand palms himself. His strokes turn quick and desperate, dragging his hand over himself while his tongue presses against the spot where your scent is strongest.

The smell of you is overwhelming.

Warm, intimate, and completely intoxicating.

It fills his lungs until it feels like it’s suffocating him, and the effect it has on him is immediate. His head tips back slightly, jaw falling open as a silent moan escapes him, eyebrows knitting together while his eyes squeeze shut.

It makes his head spin.

So much so that he sometimes finds himself hesitating, unable to decide what he wants more—keeping them wrapped in his palm while he jerks himself off, or shoving them back against his face and breathing you in until his thoughts go hazy.

Eventually he solves the problem in the most practical way possible.

The next time the opportunity arises, he steals two pairs instead.

That way he doesn’t have to choose.

One stays wrapped around his cock while his hand works over it, the fabric catching every movement as his hips start thrusting into his grip again. The other he presses against his face, breathing you in while his strokes grow faster and sloppier.

It’s embarrassing how quickly it becomes routine. The way his body responds almost immediately the moment he has them in his hands.

At some point he even starts using them to muffle the sounds he can’t quite hold back, pushing the fabric between his teeth while his hand squeezes tight around his cock. The taste of your scent mixes with his saliva, making his head feel light, eyes watering as he breathes through his nose, the smell of you flooding his senses.

He looks completely wrecked like this.

Jaw slack, lips parted as soft sounds slip past them. His brows pull together, eyes squeezed shut while color spreads across his cheeks. There’s a pretty flush blooming across his face and down his neck as his hand works harder, grip tightening while he imagines the way your pussy would squeeze around him instead.

The thought alone nearly makes his hips stutter.

There are moments—brief ones—where guilt creeps in.

Especially when you come to him one day looking worried, talking about how some of your things have gone missing. Wondering out loud if there might be some kind of pervert lurking around the village.

He listens quietly while you talk.

Because technically, you’re not wrong.

There is a pervert.

Just probably not the one you’re expecting.

And despite the small flickers of guilt that surface every now and then, it never actually stops him.

Because he’s grown far too fond of it by now.

He likes the way your panties feel wrapped around his cock. Likes the way they smell. Likes the way the thought of you makes his hand move faster until he’s spilling sticky cum all over the fabric.

And then one day—

you catch him.

“The hell do you think you’re doing?”

Your voice cuts through the room like a blade.

Senku freezes instantly.

For a moment he just stares at you, eyes wide, brain struggling to process the situation he’s just been caught in. Your panties are still in his hand. His cock still half-hard where he’d been jerking himself off seconds ago.

“…Are you serious right now?” you continue.

There’s a strange tone to your voice. Not quite angry, nor amused.

Just… disbelieving.

Your eyes flicker between him, the fabric clutched in his hand, and the obvious mess he’s made of himself.

“So you’re the one stealing my stuff, huh?” you say slowly.

His brain short-circuits.

He opens his mouth like he’s about to explain. About to come up with something logical. But nothing comes out.

The embarrassment hits him all at once.

Heat floods his face, shame curling tight in his chest as he suddenly becomes very aware of how pathetic he must look right now. Your panties in his hand. His cock still twitching. The evidence of exactly what he’d been doing impossible to ignore.

You step closer, standing in front of him now.

And instead of sounding angry—you start teasing him.

You’re not actually mad—far from it, actually. If anything, the sight of Senku using your things like that does something strange to you. But you want to make him squirm a little first. Make him worry. Maybe watch him get a little flustered.

What you don’t expect is how hard it hits him.

“Oh wow,” you mutter, looking him up and down. “Didn’t realize you were that much of a pervert.”

The words hit harder than he expects.

Not because they’re cruel.

But because they’re true.

Senku has never really been scolded like this before. Not like this. Not when he’s already worked up, exposed, and caught red-handed.

His throat tightens, breath catching as something twists in his chest. He’s already wound up from moments ago, emotions running high, and now you’re standing there pointing it out like it’s the most obvious thing in the world.

It becomes too much.

His eyes start to sting.

A few tears slip out before he can stop them.

You didn’t mean to make him cry that much. Maybe a couple stray tears, sure—but not this.

Still… the sight does wonders for your ego.

His eyes are a little bloodshot now, his nose slightly snotty, breath still shaky as he looks up at you. And instead of backing off, you find yourself kneeling instead—cooing gently as you start sliding your panties off your hips.

Your hand snake between you to wrap around his soft cock. It hardens instantly at your touch, a broken, helpless whimper escaping him as you stroke him, eyes still glossed with tears.

as you straddle his hips. Your bare pussy, slick and wet, presses against him, grinding slowly at first, letting him feel every inch of you, every drip of your slick, every small twitch of his hips beneath you. His tip nudges just perfectly against your clit, drawing another strangled whimper from him, and every so often you sink almost all the way down, only to pull back with a wet, satisfying pop. His groans and little whines fill the space, ragged and desperate, and you can feel him quivering beneath you.

You take your time. His chest rises and falls in uneven bursts, hands twitching, eyes screwed shut, little whimpers and choked noises spilling from his throat. Each sloppy, needy grind, each sloppy bounce of your hips drives him higher, and the room is full of the scent of him, of you, of the mess you’ve already made together.

The moment you finally sink fully onto him, he lets out the most obscene, pornographic moan you’ve ever heard in your life.

A sound you genuinely didn’t think he was capable of making.

Your hand flies to his mouth, pressing firmly, muffling the rest of his sounds, while you ball up the panties you threw aside and use them as a gag. Drool slips from the corners of his mouth, soaking the fabric. His tiny, garbled noises tumble out, desperate and broken:

“Mmff… ahh… p-pwease… mngh!”

He cries quietly, tears streaking down his flushed cheeks, as you continue to ride him. Bouncing up and down, up and down on his cock, he can do nothing but take it.

His body convulses, little whimpers and muffled sounds still slipping out around the gag, while he feels you clenching tightly around him.

Afterward, you slide off gently, cradling his face in your hands. His eyes are red, a few tears still clinging, nose damp, and he curls instinctively into your chest. You kiss each tear away, gently wiping his face, whispering soft words into his ear—how amazing he is, how much you love him, how proud you are of him. He shivers, body relaxing into yours, and for the first time in a long while, he feels completely safe and cared for.

an: I am so insane for this man it needs to be studied... lord save me or I have sinned.