You must be getting bored
Character(s): Senku Ishigami
Fluff
You stare at your lips in the mirror some color faded and smudged around your lip "you must be getting bored this mustn't be the most exciting experiment and I still can't make it transfer proof" sighing to turn to Senku who face and lips are covered with different shades and visibility of lipstick,that are almost unnoticeable with how red senku face is.
Who said you couldn't make your favorite shade of lipstick in the Stone Age? No one and that’s precisely why you’re sitting at your own desk with beeswax, crushed flower petals, red berries, and everything else you need to recreate the color you used to wear all the time back in the modern world.
There’s just one problem. You have nowhere to test the shade.
Your hand? Nope you’d risk mixing the pigments.
A rag? Absolutely not. With Senku’s chemical experiments around, who knows what kind of residue might melt your lips off.
So the next best thing?
Senku himself.
“Senku! Can you come here for a second? I want to try a little experiment!” you call out from your lab beside his. Somehow, despite the labs being ten feet apart, he still arrives out of breath.
“So… what’s the experiment?” he pants, bracing himself with his hands on his knees.
“Come here” you say, motioning to the stool beside you as you finish mixing the pigments.
He watches silently as you blend the colors into a soft pink paste, his crimson eyes following every movement as he sits. Then you dab some onto your lips.
“Are you making lipstick?” he asks with a short laugh, pulling the tiny bowl closer to inspect it. “You could’ve just asked me to make it.”
“Mhm, I know. But I want to get the shade just right! Does it look like my usual color?” You turn away from the mirror to face him.
“How am I supposed to know? It’s not like I stare at your lips all the ti— I have more important things to do,” Senku grumbles. You might have believed him if the tips of his ears weren’t turning pink.
A perfect time to execute your plan.
“Maybe it needs to go on a different surface—Muha!”
You lean in and kiss Senku on the cheek, chaching him off geard then gently take his face in your hands, turning it toward the light to check the color. Senku freezes, stunned, the blush on his ears now spreading across his cheeks.
“It’s too light,” you mutter, adding more red to the mixture. You apply the new shade to your lips… and kiss him again.
This time, when your lips brush his cheek, Senku actually makes a sound, something between a gasp and a startled hiccup and his posture stiffens
You pull back just enough to examine the second print. “Hmm… getting closer,” you tilt his chin lightly. His skin is warm beneath your fingers warmer than usual.
Senku swallows hard. “Y-You know,” he says, voice cracking just a little, “there are far more efficient ways to test chemical pigments than… than this.”
“Oh really?” You dip your finger into the bowl, swirling the color thoughtfully. “Name one.”
He opens his mouth. Closes it. Opens it again. Nothing comes out.
That alone tells you everything you need.
You smile. “That’s what I thought.”
You reapply the adjusted shade to your lips, leaning forward again. Senku squeezes his eyes shut, bracing like he’s preparing for an explosion. The kiss lands a little closer to the corner of his mouth this time—soft, deliberate, warm.
He lets out a choked breath. “You did that on purpose.”
“Maybe,” you sing-song.
You grab his face again before he can escape the moment, turning him toward the light. This time, the imprint is perfect—smooth, even, and exactly the shade you’d been wanting But you take your time inspecting it anyway, fingertips brushing along his jaw. His blush deepens.
“It’s perfect,” you declare. “Exactly the color I used to wear.”
“Great,” he says weakly. “Fantastic. Mission accomplished.”
“Oh, we’re not done,” you say, showing him the bowl. “I need to test its durability.Transfer resistance.”
Senku’s eyes widen in panic. “Transfer resis—?”
You cut him off with another kiss—this one full on the cheek, lingering just a second longer than you have to. When you pull away, he’s frozen again, hair practically sparking with flustered static.
You grin. “For science, Senku.”
He somehow manages to look both betrayed and hopelessly smitten. “Yeah,” he mumbles, rubbing the back of his neck. “For science.”
"I think it needs more testing in the transfer part" you mutter quickly whipping around and adding more the mix "of course this will be more testing is that alright with you?" Looking up as you asked him, still mixing "yeah..I'll have the others do the work" Senku looked off to the side avoiding your gaze "great!" Cheering you dab the new formula of lipstick on your lips
You quickly pecked his forehead frowning at the result a red lip mark as bright as ever visible you hummed turning back around
"I need to find the right formula so it won't transfer"
. “Then we can move on to refining the texture next.”
“Oh? And how do you suggest we ‘test’ that?”
His face goes pink again, but he forces himself to stay cool. “You’ll need to check how long the pigment lasts,” he says with a shrug, “so repeated contact under controlled conditions would be the ideal approach.”
You stare. “…Are you telling me we need to keep kissing?”
“For science,” he says, dead serious.
You laugh, leaning into him, forehead brushing his. “Right. For science.”
☆゚.*・。゚☆゚.*・。゚☆゚.*・。゚☆゚.*・。゚☆゚.*・。゚☆゚.*・。☆゚.*・。゚
You stare at your lips in the mirror some color faded and smudged around your lip "you must be getting bored this mustn't be the most exciting experiment and I still can't make it transfer proof" sighing to turn to Senku who face and lips are covered with different shades and visibility of lipstick,that are almost unnoticeable with how red senku face is.













