Work Text:
“Where the hell are you taking me?”
“Stop whining and just follow me, you nerd.”
Senku barely had time to register the hand clamped around his wrist before you were already dragging him out of the lab, fingers warm and insistent as they pulled him away from the cluttered workbench. Chrome’s voice cut in somewhere behind them—confused, vaguely offended—his words tumbling over each other as he tried to protest.
You didn’t even slow down.
“I’ll make it up to you, Chrome—promise!”
“I–but we—whatever…” came the defeated reply.
Senku didn’t bother turning around. He knew better than to fight this once you’d decided on something. Still, irritation prickled under his skin as he tried one last time.
“Couldn’t this have waited?”
“No.”
You stopped abruptly, forcing him to halt with you, then pulled something from behind your back. A strip of cloth.
“…You’re joking,” he said flatly.
“Put it on.”
He stared at it for half a second, unimpressed, then sighed and took it from your hand. The blindfold slid into place, plunging his vision into darkness. Immediately, his other senses sharpened—the cool brush of night air against his skin, the faint scent of earth and grass, the steady pressure of your fingers laced through his as you tugged him forward.
“Good boy,” you murmured, a teasing lilt to your voice.
“Don’t make me regret this,” he replied, tone dry but eyes tightening against the blindfold.
“Boo,” you said. “You’re no fun.”
He walked because he trusted you.
Which was, objectively speaking, reckless.
Leaves crunched beneath his boots as the ground grew uneven. You slowed slightly, guiding him more carefully now, your grip tightening whenever the terrain dipped.
Then you stumbled.
“Oops!”
Senku stiffened, muscles coiling. “Are you trying to kill me?”
“No,” you said, almost cheerfully, “but this would be a really good way to do it.”
He clicked his tongue, the sound sharp in the quiet night. “Ah, so this is a kink.”
“Ha—you wish.”
You laughed, adjusting your hold on him, you steered him forward a few careful steps, the ground beneath shifting from rocks and roots to the soft crunch of fresh grass. The air felt more open here—cooler, quieter.
“Wait right there,” you instructed suddenly.
“Yeah, like I can see where I’m going,” he muttered, tone dry, one hand flexing in the air as if to measure the invisible terrain.
“Don’t talk back to me.”
“…Yes, ma’am,” he said, voice flat but carrying the tiniest hint of reluctant amusement.
A faint rustle sounded to his right, he assumes it must be some sort of fabric. He could hear the subtle thud of something being placed, then a quiet shuffle of movement.
“Okay,” you said softly after a moment. “You can take it off now.”
He hesitated, fingers brushing the blindfold, then, slowly, he lifted it away.
The view hit him all at once.
A blanket spread neatly near the edge of the cliff, weighed down at the corners with smooth stones. A small collection of snacks sat—nuts, dried fruit, and a small cake that looked almost too pretty to eat. And beyond it all, the sky stretched wide and endless, stars scattered thickly across the dark like spilled sugar, impossibly bright against the dark canvas of the night sky—thank goodness theres no light pollution in the stone world.
For once, Senku didn’t speak. His mouth parted slightly, eyes wide, taking in the scene.
“I know you don’t really care about your birthday,” you said, suddenly a little quieter. “Because—”
“It’s just another cycle of the Earth’s rotation,” he replied automatically, almost defensively.
“Yeah… that,” you said, rolling your eyes, a small smile tugging at your lips. “But I still wanted to do something. So—ta-da.”
He allowed his gaze to sweep over the setup, lingering on the blanket, the scattered snacks, the cake—then upward, to the night sky, and finally back at you. Something unreadable flickered across his face, the usual sharp, calculating expression softening just slightly. He exhaled, long and quiet, as though admitting something even to himself.
“…You’re ridiculous,”he muttered, voice low, almost begrudging
“I had Francois help with the cake,” you added quickly, gesturing. “It’s—well. Kind of a strawberry shortcake? Sort of. I mean, no strawberries, obviously, but the whipped cream’s goat milk and—”
He walked past you before you could finish, lowering himself onto the blanket. Straight-backed, steady, eyes returning to the sky like he was anchoring himself in something familiar.
You followed, sliding down beside him, letting your shoulder brush against his. The night was quiet except for the occasional rustle of grass, the wind teasing across your arms.
Senku’s lips twitched in the faintest trace of a smile as he began naming the constellations with his usual obsession: “Orion… Betelgeuse is slightly off from the last time I measured… Cassiopeia is clear tonight… Quadrantids are peaking…”
You let him go on, a soft smile tugging at your lips as you watched him practically glow, animated and absorbed in the patterns above. He was a nerd in the purest sense—methodical, precise, completely enraptured by the constellations. And yet, somehow, seeing him like this—so alive, so unguarded—made the stars themselves seem a little dimmer by comparison.
Then, while his gaze was caught by a particularly bright streak of meteor, you couldn’t resist. You dipped a finger into the whipped cream on the cake. swiftly smudging it across his cheek.
He turned toward you immediately, eyes widening, jaw tensing in incredulity. “Did you just—”
Before he could finish, you leaned in and licked it off. The sweet tang hit your tongue first, then the warmth and softness of his skin.
“Mmm,” you murmured, playful and soft at the same time. “This is pretty sweet.”
Senku froze. For a second, nothing moved except for the faint wind ruffling your hair. Then, without thinking, he mirrored you—frosting smudged across your lips, and before you could react, he leanedin to taste it himself, pressing his mouth to yours. Slow at first, careful, tasting the sugar, and then more confident as he realized you didn’t pull away.
When he finally broke apart, just enough to breathe, his lips curved slightly in that rare, unguarded smile that made your heart stutter.
“Yeah,” he murmured against your lips, voice low and warm. “Really sweet.”
You let out a soft laugh, brushing a strand of hair behind your ear, and for a moment, the night seemed suspended around you. The blanket beneath you, the faint scent of grass and earth, the twinkling of the stars above—it all felt impossibly still.
You exhaled, letting the quiet stretch before you spoke again. “Isn’t it pretty?”
Senku didn’t answer right away.
He was looking at you. Not the stars, nor the streaking meteors flashing across the dark sky above—just you. The way your eyes reflected the faint glow of moonlight, the gentle lift of your lips as you smiled, unguarded, unaware. His chest tightened slightly, and for once, there were no calculations, no strategies, no internal debate.
“…Yeah,” he finally sighed, voice quiet, almost reluctant. “It is.”
You turned to him, frowning lightly. “You’re not even looking!
He quirked a brow, a smile tugging at the corner of his lips. “I’m multitasking,” he said, voice teasing. “Can’t help it if you’re more interesting than the sky.”
“You trying to distrcat me,” you muttered, though your chest warmed at the compliment.
“Hmm,” he drawled, eyes glinting, hands shifting subtly beneath your sides. Then, with the ease of someone who knows exactly what they want, he rolled you gently, pulling you down so that you straddled him. “Now we both get what we want,” he murmured, voice low and confident. Because you wanted to watch the stars, but he—well, he wanted to watch you.
From this angle, he could look up at your face, catching every shift of expression, every subtle curve of your lips. And above you, the night sky stretched infinite and impossible, meteors streaking like silver threads across a deep indigo canvas. Somehow, this—the two of you here, the stars—was the best view he’d seen in a long, long time.
“You’re lucky it’s your birthday,” you murmured, breathless, tilting your head slightly.
“Yeah,” he replied, eyes lidded, voice husky. “Luckiest guy in the world, huh? Gonna let me get what I want?”
“Pervert,” you whispered, laughing softly, leaning just a fraction closer. “What if someone comes looking for us?”
placing his hands firmly on your hips, rolling them against his in slow, teasing circles. “With the way you got everyone in on this plan, I doubt they’ll bother us for a while.”
A low, muffled noise escaped your throat as you planted your palms on his chest for balance, feeling the heat of him beneath your fingers. You began to move, grinding yourself gently against him.
“That’s it, baby… just like that,” he murmured, voice low and ragged, hands pressing harder into your hips, guiding you.
Your lips found his again, sloppy and hungry, tasting each other with a careless urgency. The kiss deepened, teeth occasionally catching, tongues exploring, only to pull back, a thin string of saliva connecting the two of you.
It didn’t take long before you became acutely aware of him beneath you, the bulge bumping and rubbing against the sensitive nub of your clothed clit. A soft, involuntary moan escaped before you could stop yourself, a shiver running through your spine that he seemed to feel instantly.
“We—fuck… we can sit here and you can grind on me all day,” he said, voice catching slightly, “but you seem to be… growing impatient.”
“Please…” you breathed, voice barely more than a whimper, lust dripping from every syllable.
A smirk tugged at his lips, eyes half-lidded as he shifted slightly. “C’mon. You can do it yourself.”
Your legs wobbled as you lifted slightly, slipping your soaked panties down. You didn’t miss the way his gaze followed, sharp and hungry, drinking in the wet trail you’d left behind. Quickly, you straddled him again, this time lower on his thighs. He lifted his hips with perfect timing as you tugged his tunic up and out of the way.
Seems he was just as eager as you are. His cock gleamed, tip flushed pink and swollen, dripping with precum. You itched to take him in your mouth, to feel the weight of him resting on your tongue, but you shook the thought away, letting your hand wrap around his base instead.
He hissed sharply at the touch, eyes squeezing shut.
“Let me make you feel good,” you whispered, pressing a soft kiss to the sensitive inner skin of his thigh. Your hand moved up and down his length, slow and rhythmic, twisting upward, squeezing lightly on the way down, over and over. The friction of your palm against him was enough to make him tremble beneath you.
You knew him wholly—only you could work him like this, hit every spot perfectly.
His groans were soft at first, attempts to bite them back, but as your other hand drifted up to rub at his slit, every ounce of control left him. Filthy, wet whines and groans tumbled from his mouth, each one driving you to stroke him faster.
“Does it feel good, Sen?” you asked, voice low and teasing.
“Nghh—so…good,” he groaned, hips jerking involuntarily against your hand.
You smirked, teasingly dragging your thumb along the tip, letting the oozing precum coat your fingers, leaning forward so your lips hovered just above him. “You want more, huh?” you whispered.
When he barely nodded, desperate and needy, you leaned down, pressing a tentative kiss to the head, tasting him. The shiver that ran through his body made you grin. Slowly, you sank lower, wrapping your lips around the tip, teasing, sucking, flicking your tongue over the swollen, pink flesh. He hissed, low and ragged, the sound vibrating deep in your chest as you bobbed just enough to make him whine.
His hands tangled in your hair, gripping lightly at your scalp as you let your mouth explore him, taking him in slowly, letting him brush the back of your throat before retreating, your lips twisting teasingly to give soft kitten licks to the sensitive tip.
“You—fuck… you’re… so good,” he gasped, words catching in his throat as you sucked and licked, tracing every inch with precise attention.
His hands tighten in your hair, grip firm but not cruel, as he guides you down, each thrust of his hips into your mouth sending a sharp gagging whine from you. Your nails dig into his thighs instinctively, leaving crescent marks, as your lips and tongue work frantically to accommodate him. He’s relentless, pushing that swollen tip past the back of your throat.
Every thrust of his hips makes your cheeks burn and your throat ache, but you adjust, tilt, swirl, and lick.
Your hand slides up to the base, stroking him in time with the thrusts of your mouth, feeling every hard pulse, every twitch under your lips. You gag again, swallowing around him, eyes watering, letting him fuck your mouth fully. “Mmm—nghh…so close… I’m gonna—” His words break into ragged moans, and you redouble your efforts, sucking harder, bobbing faster to squeeze out every delicious drop.
He groans, the fingers tangled in your hair gripping tighter, holding you in place as his hips jerk violently. “F-Fuck…oh God…shit—” Every twitch of his limp cock inside your mouth makes your heart clench as you milk him, tongue working over him, letting him cum deep down your throat. You swallow obediently, moaning softly around him, letting your lips linger even as his release rocks through him.
But you’re not done. Even as he comes, you don’t stop. Pulling back just enough for air, your hand takes over fully, stroking him with slow, deliberate precision, working him back to full mast.
“Fuck woman…I’m still–mgh–sensitive…” His words are broken, ragged, and the way his hips rut against your palm makes a shiver run through you.
You giggle softly at his protest, “Your mouth is saying one thing but you body is saying another”
With a wicked smile, you climb on top, straddling his hips bare, grinding slowly, letting your slickness glide over him. His hands find your hips instantly. “m’gonna…make you feel good again,” you murmur, looking down to watch as his cock slid between your wet folds.
He slips inside you so easily, and your body immediately clamps around him. “So… tight,” he groans, Adam’s apple bobbing as he thrusts up to meet you. Every inch of him stretching you, filling you completely, makes your head fall back, moans spilling freely from your lips.
You grind down on him, rocking slowly, savoring the delicious friction as your slick coats him, making each stroke glide smoother than the last. His hands clutch your hips, thumbs pressing into your flesh, guiding your movements while his hips jerk upward instinctively, chasing the sensations that make him whine low and ragged.
“F-fuck…you’re…so warm…so wet…”
“Yeah?” you murmur, teasingly, tilting your hips.
“Yeah… sweetest fucking pussy…” His words are broken by ragged moans, hips snapping up to meet yours. “like it was made for me,”
He groans, voice thick and desperate, hands gripping your hips tighter as he drives up into you, every deliberate thrust matching the slow rhythm of your grinding. His eyes, usually sharp and calculating, are now glazed and hungry, drinking in every curve of you, every arch of your back, every shiver that ripples through your body as you move.
“Look at you… ” he rasps, voice ragged, nearly lost to the rhythm of your bodies. “So perfect… bouncing on top of me like that…”
You tilt your hips a fraction, letting him sink deeper, and he groans again, the sound low, wet, vibrating in your chest. Each push of his cock into your tight, slick walls is slow but insistently deep, giving you time to feel every inch of him streching you.
“Feels… so good,” he murmurs, breath hitching as his thumbs dig into your hips, pulling you flush against him.
He bites his lip, struggling for control as his hands roam up your sides, lingering at your ribs, then pressing into your back as you ride him. “I can’t—can’t stop looking at you— at how tight you take me…” His voice cracks, a low moan of awe escaping him. “and the stars… fuck… everything—just you right here,”
You tilt your head down to look at him, letting your lips brush against his ear, teasing, “Like what you see, Sen?”
He groans, hips bucking involuntarily, utterly caught between the feel of you and the sight of you moving perfectly atop him, framed by the dark velvet of the night sky and glittering stars.
You slow your movements just enough to let him savor the view, letting your weight press into him, grinding softly while maintaining eye contact, the tension thick and hot between you. Each little flex of your hips, each slow roll, drives him further toward the edge, making him gasp, whine, and groan—pleasure, admiration, and desperation all tangled together.
His grip tightens, breath stuttering, and then it’s too much.
He whines again, hips jerking faster, hands clutching your hips with desperate insistence. And then—suddenly—he shudders violently, a strangled groan ripping from his throat as he cums deep inside you.
“Oh—fuck…!” he rasps, body trembling beneath yours, eyes squeezing shut as he spills, warm, milky ribbons filling you.
You gasp, your chest rising and falling rapidly, and slowly lift yourself off him, the wet weight of him dripping out between your slick folds. A bead trails down, and you can’t help but let out a soft laugh.
“Oops,” you murmur, shaking your head, the mess glistening faintly under the moonlight.
Senku just stares up at you, chest heaving, eyes half-lidded and glazed over with lust and awe, and for a moment he doesn’t even move—like he’s frozen in disbelief at what just happened.
“You better hope I don’t get pregnant,” you tease, voice light, playful, though your cheeks flush slightly at the thought.
Senku’s lips twitch into the faintest, almost devilish smirk. “Hmm… seems like you’d like that,” he murmurs, voice low but teasing, not an ounce of shame anywhere in his expression.
You lightly punch his shoulder, hard enough to sting but not hurt. “You better not be getting any ideas,” you warn, though your lips twitch with amusement.
He chuckles softly, a low, satisfied sound that vibrates through his chest, and wraps an arm around you, pulling you flush against him. “No promises,” he murmurs, resting his head near yours, eyes glinting with mischief—but warmth and adoration too.
You sigh, letting yourself melt against him, the stars above, the night around you, and the soft warmth of his body making the world feel impossibly still and perfect.
“Happy birthday, Senku.”