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It starts as a passing thought, but Yukimiya knows better.
He knows when something inside him isn’t just going to stay a thought.
He’s had this... ache for weeks. It’s not new — the envy that twists in his chest every time Isagi’s name echoes through Blue Lock’s halls. The way Isagi runs, the way he breathes, the way he talks about football like it’s the only holy thing worth worshipping.
Yukimiya should be above this. He should pray it away— he did that once, when he was sixteen. Bent over the side of his bed, knuckles white against the sheets, reciting half-remembered verses to get rid of the images of boys in the locker room. He thought he’d outgrown that part of himself.
But Isagi makes him want. Makes him crave.
Makes him fist his dripping cock angrily when he misses an opportunity to score a goal.
So when he finds Isagi alone in the showers after a late night of extra drills, Yukimiya knows exactly what he’s about to do.
---
Isagi doesn’t hear him at first, just the slap of water against tile, the low hiss of steam. His back is so soft and pale under the harsh lights. Broadening shoulders, the curve of his waist, the way his ass rounds out just enough that Yukimiya wants to sink his teeth into it. The way his thighs are calling to Yukimiya right now. The puffy hole and the soft cock that's 3 quarters of Yukimiya's.
He should turn around. He should say something holy, something forgiving.
Instead, he puts his towel aside, takes of his glasses and places it at the sink before he steps forward, cock already half-hard with something like shame pooling in his gut.
Isagi startles— half-turns, wide-eyed, water dripping from his hair.
Down to his nape, back, waist, the curve of his ass and slowly down his thighs.
“Yuki— huh? What’re you—?”
Yukimiya kisses him so suddenly and harshly it shuts him up. He kisses him like it’s the only way to swallow down the thing that’s rotting him from the inside. Tongue and teeth, swallowing Isagi’s soft, surprised whimper. He pushes him back, palm flattening against Isagi’s chest, feeling the quick hammer of his heart under his ribs.
“Don’t—” Yukimiya mutters, lips brushing Isagi’s throat, his pretty neck that Yukimiya had thought looked pretty with marks littered on it. “Don’t talk. Just— just let me.”
Isagi could push him off. He could say no— but he doesn’t. His body sags against the tile, slick and warm under Yukimiya’s hands. His cock twitches, half-hard slowly, brushing Yukimiya’s thigh.
---
They don’t speak. There’s nothing to confess here except the sound of skin against skin, the way Yukimiya hitches Isagi’s leg up over his hip, the sting of tile against Isagi’s back. He pushes in slow, too slow — but the moment the head of his cock slides inside, the guilt splinters.
He’s in. He’s inside him.
He's dreamt of times like this.
“God—” Yukimiya breathes, eyes squeezing shut. A single word, half-prayer, half-curse. He fucks into Isagi like he’s trying to empty himself, and he is. The slap of hips, the wet slide, the little choked moans that Isagi tries to bite down on. It's all virgin, now tainted.
The echo of his balls against the muscles of Isagi's ass will forever be embedded into his brain, skull, and dick.
It'll be slotted in his mind, right next to the verses he was conditioned to remember and follow.
He thinks for a second— This is wrong. This is—
But then Isagi clenches down around him so tightly and his head goes white. The guilt slides away like soapy water down a drain.
The shorter boy is so tight, Yukimiya's sure he blacked out for a second.
---
When they come, it’s messy. Isagi spills first, shuddering, back arching off the wall. Yukimiya watches the streaks of it wash down the tile. He pulls out just in time, jerks himself, spills hot over Isagi’s stomach. Painting Isagi's abs with white sticky substance.
He kisses him again, softer this time. Regret is a ghost at the back of his tongue, but it never quite makes it out. Everything else makes it out but his thoughts.
Afterward, Yukimiya lets the water hit his face until he can’t feel the heat anymore.
I’ll pray tomorrow, he thinks, chest heaving, forehead pressed to Isagi’s.
Tonight, I’m just a man.
It’s what he tells himself the first time.
And the second.
And the third.
---
He doesn’t mean for it to get… casual. Really. But it's not his fault he's got a dick that decides it needs to get hard the moment him and Isagi are in any places alone together. It now feels... Odd.
But Isagi looks at him the next day like nothing’s changed — just bumps his shoulder against Yukimiya’s in the corridor, grins that stupid grin that makes Yukimiya’s chest feel scraped raw. It should be awkward, humiliating, something they never speak of again. But instead, Isagi just shrugs and murmurs, “Same time?” with a stupid little smirk, like it’s the most natural thing in the world to let Yukimiya fuck him up against shower tiles until the brown-haired is still rocking up in him while his dick is soft.
And Yukimiya, who still tries to bow his head in prayer before bed, who still touches the rosary his grandmother gave him when he thinks no one’s looking, doesn’t say no. Never.
---
The worst part is how easy it becomes.
It’s easy when they’re exhausted after drills and Isagi pushes him into the last stall, still half-laughing, voice going breathy when Yukimiya’s teeth graze his throat. Breathes him in.
It’s easy when Isagi leans over the bench in the empty locker room and Yukimiya doesn’t even bother taking his shirt off— just yanks Isagi’s shorts down, spits on his cock, and slides in, forehead resting between Isagi’s shoulder blades.
It’s so fucking easy when Isagi looks back at him over his shoulder, eyes half-lidded, whispering, “Faster, Yuki. Don’t think. Just do it.”
---
He tries to tell himself it’s still just a mistake, just a one-off sin stretched thin and fragile between stolen moments. But every time Isagi spreads his thighs for him, the lie crumbles.
Every time Isagi’s voice breaks into a soft ahn...! that makes Yukimiya’s stomach twist with sick, unholy hunger, he knows he’ll do it again.
And every time he finishes —pulling out just enough to see it drip onto Isagi’s flushed skin— he looks up at the ceiling and thinks:
Forgive me. Forgive me.
But he never means it enough to stop.
---
It’s what he tells himself.
I'll pray tomorrow.
He tells himself that every night, while Isagi wipes himself off with a grin, still calling him Yuki, like they’re just teammates. Like they’re just boys with dirt under their cleats, no guilt, no shame, no desperate need sticking to their skin.
One day, Yukimiya thinks, with his hands pressed together like they’re stuck, he’ll have to mean it.
But tonight, Isagi’s fingers curl into his hair, tug him down for a filthy kiss, and the promise of tomorrow slips away with the sound of the shower drain and addictive wails.
---
Sometimes it's... A lot in one.
The first one is always the worst. Yukimiya tries to hold back, tries to keep it quiet, a hand over Isagi’s mouth, palm pressed flat to the shower wall while he pushes in deep, hips snapping hard enough that Isagi’s ass makes that wet, obscene slap against him that resounds against the tiles.
“Shh— quiet, Isagi— fuck, keep it down—” he mutters, even though he’s the one gasping, his voice breaking whenever Isagi clenches around him like that.
Isagi’s eyes roll back when Yukimiya bites at his neck, muttering filth he’ll pretend he didn’t mean later. “You’re so fucking tight, your hole always— always so fuckin’ perfect for me—”
---
The second time, they’ve barely rinsed off. Isagi turns around this time, chest pressed to Yukimiya’s front, arms looped around his shoulders. Yukimiya’s cock slides back in too easy, hot and swollen, precum smearing everywhere that matters.
“You like this?” Isagi pants against his ear, breathless, hungry. “You gonna fuck me again, Yuki? Yeah?”
Yes. Yeah. Please. Yes. Always.
But instead he says.
“Shut up,” Yukimiya growls, but his hips stutter and he’s grinding in circles, dragging Isagi’s whines out. “Shut that pretty mouth. You want someone to hear how fucked you sound?"
Hah—
"you want ‘em to know I’m splitting you open, baby?”
Baby. That's a new one.
The words taste wrong on his tongue but feel so right when Isagi moans for him — not just soft or shy but... hungry— whimpering and whispering, more, more, don’t stop , don’t pull out yet...!
...And Isagi may have called him senpai once out of... Formal habit.
Yukimiya likes it— loves it. Isagi would probably have guessed so too when the cock in him violently throbbed then.
---
The third is where it happens.
Isagi’s clinging to him, nails digging into his back, sweat and steam making it feel like there’s no air left at all. New scars forming like trophies. Yukimiya fucks him through it— dizzy, teeth bared, the slap of their bodies echoing too loud off the tiled walls. They could hear the squelches, the way Isagi's fucked ass was sucking Yukimiya in so good it clenched.
Isagi gasps next to Yukimiya's ear softly, “Inside. Tonight, Yuki — just tonight, come inside—”
And Yukimiya wants to say no, wants to say I don’t do that, I can’t, I shouldn’t—
But instead he rasps, “Baby— fuck… fuck...!”
His vision goes white. He braces Isagi up by his thighs, fingers bruising, and sinks in deeper than he ever has, balls flush to Isagi’s ass, pulsing hot as he spills everything he has inside him. Every last drop.
Isagi’s eyes flutter, lashes wet. “God— I can feel it, you’re— Yuki, fuck—... you're so warm...”
They don't comment on how fuller Isagi's belly looked, even if slightly.
---
They don’t say anything for a moment — just pant against each other’s skin, hearts pounding so hard Yukimiya swears they’re echoing in his skull.
He pulls out slow, dizzy, watches it drip down Isagi’s thigh — a filthy, sticky testament to the guilt he can’t keep pretending to wash away.
His own dick covered in cum.
He’ll say I’ll pray tomorrow.
He’ll say Never again.
But the way Isagi’s hand slides down to smear the mess between his legs, lips curling into a wicked little grin — Yukimiya knows he’s lying.
When the water runs cold and Isagi’s breathing finally steadies, Yukimiya stays pressed to him, forehead buried in the curve of his shoulder. He can still feel it— the warmth and tightness inside Isagi, the soft flex of muscle that milks every drop from him like it belongs there.
It should feel holy. It doesn’t.
It feels real.
His chest heaves. The guilt flares up — sharp, useless. He thinks of all the times he prayed to be pure, to be forgiven, to be better than this ache in his bones.
But it’s too late now.
The taste of Isagi’s skin is salt and sweat on his tongue. The memory of his own voice — baby— fuck... inside — still burns in his ears.
---
I’m only a man, Yukimiya tells himself, almost calm now, lips brushing Isagi’s temple. He feels Isagi’s soft laugh, the way Isagi’s fingers thread through his hair like it’s nothing at all. Like it’s allowed.
I’m no better than any of them. I’m not holy, I’m not pure. I’m a sinner.
His eyes drift down— to the mess leaking out of Isagi’s spent, sore hole, smeared on his own thigh, mixing with shower water at their feet.
And he... He smiles, small, sickly sweet, biting the edge of regret until it tastes like longing. He is the sin. My sin.
And tonight, that’s enough.
He kisses Isagi’s lips again, open-mouthed, desperate, tasting all that filth, that warmth, that wrongness. He lets it fill the hollow where the guilt used to live.
Tomorrow, he’ll bow his head, trace the cross over his chest, whisper old prayers to no one.
But tonight? Tonight, he’s just a man with trembling hands and a sin he’d kneel for again and again.