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The Student Council’s favoritism is apparent when Senku slides the door open, somehow still allowed to wear a lab coat on top of his uniform. Gen straightens his spine as Senku stomps in like he’s not barging in during their free period—but then again, he’d probably still do this even with a teacher in front.
“Oi, you.” Senku grabs him by the scruff and yanks him to his feet. “You’re coming with me.”
“Did they fight or…?” Someone mutters from the back, followed by another voice going, “Nah, he’s probably just grabbing Asagiri again for those crazy experiments.”
Haha.
Not wrong. Technically.
It is an experiment, and another crazy one again at that, but—
Gen blinks as he’s shoved into an empty science club room, and the next thing he knows, he’s getting the full-on kabedon experience. His back thuds against the wall, rattling the flimsy shelves beside him.
Senku’s hand plants firmly by his head, leaving him nowhere to look but up. It’s close. Too close. Close enough that Gen can feel Senku’s breath.
He swallows, the sound embarrassingly loud in the still air between them; the faint scent of disinfectant and… something sharper, chemical, curling between them.
“Senku-chan,” Gen starts, aiming for breezy but landing somewhere close to breathless, “I can’t help but notice, we are alone in this lab.”
“It’s quiet,” Senku says, leaning in. Seriously too close. “And I’m testing the correlation between pressure, friction, and ejaculation latency through layered clothing. Control condition is polyester blend uniforms. You’re the variable, obviously.”
Gen blinks, his mouth twitching into a helpless smile. “Oh, obviously.”
Senku grins. “You’ll thank me when this becomes a published paper in the Journal of Coital Physics.”
Gen looked sideways, avoiding Senku’s gaze. “Do I at least get to veto the illustrations?”
“Don’t worry,” Senku says, moving to trap Gen’s leg in between his. “Consider it an essential element.”
“That’s not the prob— ngh.”
Electricity shoots up his spine as Senku’s knee digs into his crotch. Then, without warning, Senku switches tactics; instead of moving his knee, he begins moving on Gen’s knee instead. Like he’s decided the results will be more reliable if he experiences them firsthand—after giving Gen just a taste.
(Again, his classmates weren’t wrong. It is an experiment, but probably not the kind they’d imagine.)
With a pleased hum, Senku begins to essentially hump Gen’s leg.
The steady drag of fabric on fabric turns Gen’s thoughts into static, polyester rasping against his skin with every shift of Senku’s hips. He exhales through his teeth, the sound catching when Senku tightens his grip at his waist and presses in harder. The distinct shape of him is unmistakable now, even through the layers of cloth.
It’s embarrassingly easy for his body to fall into the rhythm—a push, a grind, the faint squeak of shoes on the tiled floor—until there’s no denying the deliberate build in Senku’s movements.
Gen’s pulse hammers in his throat, his breath hitching with every increase in pressure. For a ridiculous, fleeting moment, he actually wonders if Senku is actually charting data points in his head right now, if he’s mentally jotting equations while Gen is over here, struggling to remember how to breathe.
Knowing Senku, he probably is
But if Gen can make that brilliant brain shut up for just a second…
Despite being barely touched, his own pleasure almost like an afterthought, it’s not difficult to feel the tightening of his pants. The faint sounds Senku makes next to his ear, their bodies pressed close, the thought of what this moment means and what’s possibly in store for the future…
Without thinking, Gen spins them. Senku lets out a groan as his back hits the wall—perhaps a little too hard—but Gen’s apology gets muffled against Senku’s shoulder as instinct takes over.
Gen pins him there, forearm braced hard against his shoulder and thigh wedged between his legs before Senku can so much as blink. His other hand fists in the front of Senku’s coat, yanking him forward into a grind that’s all force and no pretense.
The startled groan that escapes Senku’s throat is worth it. Gen chases it, rolling his hips with enough pressure to feel every sharp line, the burn of cloth dragging over cloth. Each shift pulls a stifled sound from one of them. Gen leans in, teeth grazing Senku’s ears as the heat spikes.
Two more hard drags and Senku jolts, his body going tight—and then he’s still. Just like that.
Gen’s eyes widen as he feels dampness on his leg. Before he can say anything, before he can even think about fairness, Senku is already taking a step back as he plants a palm on his chest to gently push him back.
It’s weak resistance, but Gen’s too flabbergasted to fight it. Because Senku calmly raises his other hand to check his damn watch.
“Three minutes and fifty-three seconds,” Senku declares, like he’s just calculated the average length of the songs in an album and not the time it took for him to finish.
Though Gen celebrates a little inside. Checking the watch meant he got distracted enough to lose his mental counter, at least.
“It’s valuable data, but it’s not the condition I needed.” Senku clicks his tongue. “It has to be controlled.”
“Then we just have to do it again.” Gen reaches for him, but Senku quickly dodges his hand and straightens his lab coat to hide the stain on his pants.
“Your free period ends in less than two minutes, and I have to do something about this”—he gestures down—“before I head to the faculty room.”
“But Senku-chan,” Gen whines. “What about me?”
Senku smirks, devastatingly hot and absolutely unhelpful. “Not my problem. Guess you’ll just have to hold it in.”
Gen stares at Senku’s back until it disappears out of view, and he’s left with the sight of the closed door.
He really left. Just like that.
How errible-tay!