Archive of Our Own

Zenitsu hadn’t meant to wake up. Really.

He’d laid there on his futon with his friends snoring gently beside him, and he had tried to go back to sleep, knowing the former water and wind pillars were in the other room. But.

The sensual sound of skin meeting skin, wet slaps of bodies connecting, sounds in Zenitsu’s sleep-ridden ears.

He turns over, crawling to press himself up against the wall. They’re in the other room next to theirs, but Tomioka-san’s arm is under Shinazugawa-san’s leg, hiking it up as he thrusts backward and forward again.

“Ah, aahhn , I can’t— ”

The filthy sounds of Shinazugawa’s moaning, and Tomioka’s hips slapping against his ass, has Zenitsu flushing from the neck down, ashamed that all the blood goes straight to his groin.

“ Shh , we don’t want any of the kids waking up, do we?” Tomioka grunts in his ear, voice low and husky and oh fuck .

Shinazugawa whines, and it’s hot as fucking fuck, the way he’s pulling at his swollen nipples as the former water hashira fucks into his wet cunt, the erotica of the situation fully on display to Zenitsu’s eyes.

Tomioka and Shinazugawa are having sex— fucking —and they think he’s asleep.

Oh, heavenly Gods above.

Zenitsu strays his eyes off to the side. He should probably go back to bed and pretend he never even saw this, Gods know how embarrassed they’d all be if they knew, and Tanjirou would berate him for willingly watching such an act.

Shinazugawa’s on his side, leg hitched up in Tomioka’s grip, and the rest of him trembles with every slow drag of Tomioka’s hips. The blanket’s kicked down to their ankles, exposing the flush of his thighs, the curve of his hip, the trembling slope of his back. One of his hands fists the pillow, the other lost somewhere behind him, clinging to Tomioka’s forearm where it wraps around him.

Zenitsu sees the way Shinazugawa’s chest moves with each breath—rising and falling in sharp, shallow pants, his nipples tight and swollen, glistening slightly like they’d been sucked or tugged not long ago. His pecs aren’t that big, not like some of the women’s he’s seen, but they’re full and soft-looking, flushed all the way up to his collarbones. One of them bounces with every slow push of Tomioka’s hips, and Shinazugawa’s body reacts like he’s been shocked—his toes curling, his spine arching ever so slightly with a strangled whimper.

His pussy is soaked, stretched open around Tomioka’s cock in a way that has Zenitsu turning his face into the pillow again, horrified by how badly he wants to keep watching. He doesn't want to be a pervert. But, oh , it’s like he’s stuck in a dream he shouldn’t be in.

Tomioka’s rhythm is slow but deliberate, like he knows exactly how to make Shinazugawa fall apart—his thrusts deep, almost lazy, like he’s taking his time wrecking him from the inside out. His face is buried in Shinazugawa’s shoulder, breath hot against his skin, free hand trailing down to palm at the curve of his stomach, then lower, pressing just below where they’re connected.

“Still with me?” Zenitsu hears him murmur lowly, trying not to let the sound carry.

Shinazugawa only gasps, nodding furiously, another high moan catching in his throat. The bed creaks beneath them. His whole body trembles like a string pulled too tight, albino hair sticking to the sweat along his cheeks and neck.

There’s something desperate in the way he clings to Tomioka’s arm, in the way he rolls his hips back to meet each thrust. It’s not just need, it’s hunger, it’s wanting so deep it shakes out of him in gasps and moans and soft, crumbling sounds that Zenitsu wishes he could forget.

But he won’t. He knows he won’t. He closes his eyes and wills his heartbeat to slow, pretends not to hear the wet slap of bodies, the way Shinazugawa mewls when Tomioka grinds in deep and stills there for a breathless second.

He pretends he’s asleep.

Even though he’s never been more awake in his life.

Tomioka shifts, his hand sliding from Shinazugawa’s belly to hook beneath his thigh again, lifting just a bit higher. The new angle punches a sound out of Shinazugawa—something high and soft and nearly tearful, a noise so intimate it makes Zenitsu’s ears burn.

He’s trying not to look. He is . But every now and then his gaze betrays him, flickering to where Tomioka’s hips rock in slow, ruthless strokes, burying deep, dragging out. Shinazugawa’s body takes him like it’s made for it, like it’s meant to be filled.

He cries out again, something between a sob and a moan, and it shatters Zenitsu a little. His voice is rough and uneven, wrecked beyond dignity.

“Don’t stop—don’t—” Shinazugawa gasps.

“I’m not,” Tomioka grits out. His rhythm doesn’t change—still slow, still deliberate, but harder now, more force behind each snap of his hips. His hand trembles slightly against Shinazugawa’s thigh, holding him open, guiding him through it. “You’re close.”

Shinazugawa whines, nodding with his whole body. He’s panting like he’s burning alive, every moan slipping out raw and needy. His cunt clenches around Tomioka with each thrust, wet and fluttering and desperate, and Zenitsu can hear it—he can hear the obscene slick sounds of it, and it makes his skin crawl with heat.

He thinks, Gods above, he’s so hot like this , and then wants to slam his head into the floor. He shouldn’t be thinking that. Not about Shinazugawa . Not while he’s being—while he’s—

He curls in on himself further, ashamed, humiliated, but still—he hears the way Shinazugawa keens, sees the tremble in his thighs, the arch of his spine, the tears shining in the corner of his eyes as he gasps through it.

Then Tomioka leans in, burying his face against the back of Shinazugawa’s neck, and murmurs something too low for Zenitsu to hear. Whatever it is, it breaks him. Shinazugawa sobs, trembling around him, whole body locking up as his orgasm crashes over him—no loud cry, no scream, just this hoarse, bitten-off noise that sounds like surrender.

Tomioka groans, quiet but guttural, and rocks in deeper one last time, pressing flush against him. His arm tightens around Shinazugawa’s waist. His mouth is moving against his shoulder—soft, reverent nothings, like he’s praying. Like he’s apologizing. Like he’s saying mine .

Shinazugawa shudders and hiccups through the aftershocks, hand still gripping the pillow like it’s the only thing anchoring him to the world.

Zenitsu stares at the floor.

They’re still moving—slow now, barely rocking, the kind of lazy, sticky grind that comes after release but isn’t quite enough to stop. Tomioka’s hand smooths over Shinazugawa’s belly again, tender in the afterglow. He buries his face behind his ear, lips brushing against sweat-damp skin, and murmurs something so low Zenitsu almost doesn’t hear it.

“Gonna put kids in you,” Tomioka breathes. “Fill you up, get you pregnant.”

Zenitsu freezes.

Shinazugawa lets out a noise like he’s been punched—sharp, high, devastating. His leg jerks a little in Tomioka’s grip, and then he’s panting, nodding, eyes squeezed shut.

“Yes,” he whispers, frantic. “Please—please, want that, want it so bad—”

Tomioka groans deep in his throat. He kisses the back of Shinazugawa’s neck again, slow and bruising, possessive. His hand moves lower, pressing gently where they’re still joined, fingers spreading over Shinazugawa’s lower belly.

Zenitsu feels it like a punch to the gut.

It’s filthy. Intimate.

And Shinazugawa is so fucking hot —flushed and wrecked, begging for it, trembling as he pants through the waves of pleasure that haven’t stopped echoing through his body. The sweat on his skin catches the low moonlight. His hair’s plastered to his face. His thighs are twitching with the aftershocks and he looks… he looks gorgeous.

Zenitsu wants to die. Or scrub his eyes out. Or scream into his pillow until his soul leaves his body.

He shouldn’t be watching this.

But he can’t stop seeing the way Shinazugawa moans when Tomioka presses in deep again. He can’t unhear the way he whimpers please , again and again, like he needs it to live.

Zenitsu turns away, digging his nails into his palm, heart pounding like it’s trying to escape his chest. Shame coils tight in his gut.

He thinks, I shouldn’t think he’s hot. I shouldn’t—I’m not supposed to—

But Gods help him.

Shinazugawa begging to be bred is the hottest fucking thing Zenitsu’s ever seen.

The smell of grilled fish and miso wakes him up.

Zenitsu sits bolt upright on his futon, eyes wide and heart hammering, because he remembers. He remembers. The sounds. The voices. The way Shinazugawa mewled. The way Tomioka grunted. The way Zenitsu lay there with his eyes squeezed shut and his whole body tense, the shame spreading from his ears to his toes.

He’d hoped it was a dream. But the ache in his stomach and the sweat in his sheets say otherwise.

“Breakfast!” someone shouts from the main room. It’s Shinazugawa. His voice is rough, but casual, like he didn’t get railed into the futon just hours ago. “Come fuckin’ eat before I throw it out.”

Zenitsu wants to melt into his bed and never move again. But Instead, like a man trudging to execution, he gets up, dresses, and walks out.

Tanjiro’s already seated, smiling wide. Inosuke is stuffing grilled onigiri into his mouth at an alarming rate. Nezuko’s nibbling daintily. Shinazugawa stands next to them like he’s not the literal reason Zenitsu’s going to hell.

Zenitsu sits last.

Shinazugawa drops a bowl in front of him and grunts. “Eat.”

He thanks him with the enthusiasm of a prisoner. He doesn’t look up. Not when he knows what Shinazugawa looks like gasping into a pillow, not when he’s been thinking about it all morning while trying not to think about it. His hands shake when he lifts the chopsticks. He barely manages two bites of rice.

“Something wrong with it?” Shinazugawa says, mouth quirking.

Zenitsu swallows. “No! It’s good. Great. You’re a really good cook. Like really, really good.”

Shinazugawa raises an eyebrow. Nezuko giggles.

Zenitsu very nearly drops his bowl. He stays silent the rest of breakfast

Later, once the others have gone outside—Tanjiro wants to go check on a nearby field, Nezuko trails behind him, Inosuke chases a crow—Zenitsu finds himself alone in the kitchen with Shinazugawa. He’s trying to dry dishes. His hands are shaking.

“You’ve been jumpy as hell all morning,” Shinazugawa says suddenly.

Zenitsu flinches. “I need to say something.”

Shinazugawa watches him carefully.

Zenitsu finally blurts, “I heard you. Last night.”

Pause. Shinazugawa blinks.

“What?”

“I didn’t mean to! I—I just woke up and—and you were—” Zenitsu gestures wildly, horrified. “You were loud! And then I realized it was you and Tomioka-san, and I panicked, and—and I didn’t know what to do—so I just laid there and pretended to be asleep and—and then I wasn’t asleep—and then—”

“You heard us?”

Shinazugawa’s voice is a choked croak. His face goes bright red.

“Oh my god,” he breathes, backing up a step. “Shit. Fuck. Fuck.” He drags a hand over his face, mortified. “That’s—fuck, that’s so—”

Zenitsu wants to disappear. “I’m sorry!”

Sanemi whirls on him. “You’re sorry? You think I wanted one of you brats fucking hearing us while we were—fuck!”

He paces. Actually paces. This is a man who fights demons like it’s nothing, but now he looks like he wants to crawl into a crack in the floorboards.

Zenitsu fumbles over his words. “I wasn’t trying to listen! I swear! And I—I didn’t even know it was you at first! I just heard someone moaning and then—and then I realized—” He clamps his mouth shut. “Okay. This isn’t helping. I’ll stop talking now.”

Shinazugawa exhales. Long. Hard. He leans against the counter, covering his eyes with one hand. “I can’t fucking believe this.”

Zenitsu rubs the back of his neck. “Honestly, I’m still trying to forget it.”

Shinazugawa peeks at him through his fingers. “You said you didn’t know it was me at first. What gave it away?”

Zenitsu looks like he might implode.

Shinazugawa narrows his lavender eyes. “Well?”

Zenitsu mumbles, “Your voice.”

Shinazugawa turns scarlet. “You—fuck off!”

He runs.