KISS ME- senku ishigami
a smiskisworld fluff!
“Oh, kiss me beneath the milky twilight
Lead me out on the moonlit floor
Lift your open hand
Strike up the band and make the fireflies dance
Silver moon's sparkling
So, kiss me”
WHAT DOES IT MEAN TO DATE?
That’s the question you’d been mulling over recently. Things were finally somewhat peaceful within the Kingdom of science— no figuring out how to make revival fluid, no wars against Tsukasas army and nothing to do but work towards building the ship. So now you had nothing but time to think about more trivial things.
Things like your long term relationship with a certain scientist.
You usually had the answers to many questions, being smarter than most did that, and if you didn’t have the answer to one you’d just ask your slightly smarter boyfriend. However, if you were to ask him this one— he probably wouldn’t know the answer to it either.
Still, you couldn’t let this one go since it was driving you crazy.
Dating.
What does it even mean?
You and Senku had decided to date back at the end of middle school. No dramatic confession, no fireworks—just a mutual, quiet understanding. You liked him. He liked you. Why complicate it?
And honestly… nothing has changed since then.
You still walk everywhere together. Still sleep beside each other, backs nearly touching for warmth. Still hug—long, comfy hugs that make the world feel steady again. Sometimes you hold hands, fingers loosely linked like it’s no big deal.
It’s comfortable.
It’s safe.
It’s… childish.
Your jaw tightens. Your thoughts are so damn childish, what are you twelve?
God, get it together, you scold yourself internally. You’re thinking about stupid shit.
But now that you’re not constantly worrying about being murdered, or petrified, or starving, your brain has space for these thoughts. Too much space.
You still hadn’t kissed. Or said ‘I love you’ even when there were moments where you could tell the both of you wanted to say it to one another. Or done anything a normal couple at your age would do.
You sigh quietly, staring at the empty table in front of you, lost in thought.
“…Knock knock, anyone there?”
Gen’s voice cuts through the air, light but teasing.
You don’t react.
He blinks. “Wow. She’s gone gone.”
Still nothing.
A moment later, a finger pokes your cheek.
“Oi,” Senku says. “Stop spacing out.”
You jolt like you’ve been struck by lightning. “W–WHAT—?!”
The sudden movement makes you knock your plate over, and your frantic scrambling draws laughter from almost everyone nearby.
“Adorable,” Gen snickers.
Your face burns. “I wasn’t spacing out!”
Senku raises an eyebrow. “You totally were.”
Before you can retort back, Ryusui plops down across from you, resting his chin in his hand, eyes sharp with interest.
“So,” he says casually, “it’s cute how you only stopped spacing when Senku called out to you! Speaking of you and Senku, how’s it going?”
Instant death. Shots were fired. He called you out.
How did he know you were JUST thinking about the sad state of your relationship?
You choke on air. “H–HUH?!”
Senku sighs. “Why is that any of your business?”
Ryusui smirks. “Because you two act like a married couple and a middle school couple at the same time. Fascinating contradiction.”
Gen hums. “Now that you mention it… you are oddly awkward sometimes.”
Your hands fidget in your lap. “We’re not awkward.”
Ryusui tilts his head. “Then why do you act like strangers when romance comes up?”
Senku answers flatly, “It doesn’t matter.”
You nod quickly. “Yeah. Isn’t this how a normal couple acts?”
Ryusui laughs—loud, bright, utterly unconvinced.
“Oh, sweetheart,” he says, leaning closer. Then he lowers his voice and whispers in your ear, “I can tell the two of you haven’t even kissed yet.”
Your entire face goes up in flames.
“Shut up,” you grunt, mortified, standing abruptly. “I’m helping wash dishes.”
You flee before anyone can say anything else.
Behind you—
Senku remains seated, arms crossed. “What’d you say to make her freak out?”
Ryusui crouches beside him. “I told her the same thing I’m about to tell you.”
Senku glances over. “Which is?”
“You haven’t kissed her.”
“…So?”
Ryusui’s jaw drops. “So?!”
Senku shrugs. “It’ll happen eventually.”
“Eventually?!” Ryusui throws his arms into the air dramatically. “You’ve been dating for over three thousand seven hundred years! Man up and make a move while you finally have time!”
Senku clicks his tongue. “…I don’t know how.”
Ryusui freezes. Then he puffs out his chest. “Lucky for you, I’m a relationship connoisseur. You may be a genius in science but I’m a genius in dating!”
He proceeds to ramble about timing, confidence, instincts, and seizing moments when adrenaline is high and emotions are raw.
Senku listens. Annoyed, but interested (not that he would ever admit to it).
Then stands. “Shut up.”
But the words Ryusui said stick.
Later that night, you’re sitting beside Senku again—this time surrounded by paper, charcoal scribbles, and calculations.
Fuel logistics.
The ship needs enough power to cross long distances without overloading capacity. You both scribble numbers, muttering under your breath.
“If we use oil exclusively, we’ll exceed weight tolerance,” Senku mutters.
“Yeah, there’s the problem with the ships capacity,” you reply. “Hmm… what if we stagger consumption?”
He pauses. “Explain.”
You lean forward, excitement bubbling. “If we calculate fuel usage per nautical mile and store it in segmented containers, we can reduce excess storage by optimizing burn rates based on wind conditions.”
You scribble rapidly. “Look—if we assume an average wind assist of 15%, we can reduce fuel load by—”
“I got it!” you suddenly shout. “We cap fuel at this amount, reserve emergency storage here, and rely on sail propulsion for the first leg!”
Senku’s eyes light up. “That’s genius, I really wanna kiss you right nooww—!” He suddenly blurts out, slurring the ‘now’ when he realises what he just said.
“So kiss me,” you jokingly say, hanging the piece of paper on the open door of the lab. A few moments later, you realise that he didn’t take your words as lightly as you’d expected. The scientist was walking closer to you by the second and for some reason you kept on backing away, until the two of you were now outside.
You couldn’t say nor do anything— I mean who could at the sight of his beautifully flushed face glowing in the moonlight? So instead you lick your lips in anticipation, staring up at the silver moon reflected in his crimson eyes as he looks up at the sky in an attempt to keep his nerves at bay.
Then… he grabs you suddenly, exhilaration surging through him—
—and kisses you.
Right on the lips.
Your brain explodes.
It’s warm. Softer than you expected. His lips hesitate against yours, like he’s half-afraid you might pull away. You can feel his breath stutter, feel the faint pressure of his thumb tightening against your sleeve as if he’s grounding himself.
It lasts only a moment—barely enough time to register that it’s real—
Then Senku pulls back as if shocked by his own actions.
Your heart is pounding so loudly you’re sure he can hear it. Your face feels hot, your lips tingling where his were, and you’re staring at him with wide eyes, trying to process the fact that after everything—
It finally happened.
Senku’s ears are bright red. His expression is caught somewhere between disbelief and panic. “…I—”
You laugh, breathless and a little shaky, the sound bubbling out of you before you can stop it. “Took you long enough!”
That makes him freeze and he thinks to himself. How can someone be so perfect?
Before he can overthink it—before he can retreat back into logic and reason—you grab the front of his shirt, fingers curling into the fabric, and pull him back down.
This time, you kiss him.
And you do it like you’ve been holding this in for years—because you have.
His breath catches sharply, a soft sound against your mouth, and for a heartbeat he’s completely still. Then he melts into it, hands finding your waist, pulling you closer until your faces are pressed together, cheeks squishing slightly, awkward and perfect and real.
You tilt your head, instinct guiding you, and deepen the kiss. Your lips part just enough to catch his lower lip, gently tugging it between yours.
The kiss grows slower, warmer, unhurried.
There’s no rush. No panic.
Just closeness.
When you finally pull back, you’re both breathless, foreheads touching, noses brushing as you laugh softly, dazed smiles spreading across your faces.
Your lips tingle. Your chest feels too full. “I love you.”
“Y’know, I love you too. And I’m 10 billion percent sure I’ll always feel that way!” He chuckles before giving you another peck on the lips.
And suddenly, you get it.
Dating isn’t about labels. Or milestones. Or what you should have done by now.
It’s this.
♟️a/n
21/12/25
2000 words
@smiskisworld/-fischll/fischll
-TYSM FOR READING MY WORK AND GIVING ME REQUESTS!!
-this is written from a request I got, I’ve never written a Senku fluff before so I hope I did him justice!! ps: not proofread or anything yet so ignore the wording and lack of info I’ll proofread one day🥹🙏
-sorry for the wait I promise I’ll get to the rest of my requests soon I’m just busy writing my ryusui fic I’m not even updating it I’m just writing so much for it lol I do this for the love of the game
-13 year old me would be so proud of me for writing about my childhood crush like aww TYSM TO THE GOAT @anajellyc for requesting this!! You’ve been here from the start and I genuinely love how u motivate me to write ily twin
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