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When he wakes, it’s to a dull ache in his gut, and an unpleasant stickiness between his legs.
“Son of a bitch.” Yuuta groans as he sits up, blearily wiping the sleep from his eyes. Ever since he started testosterone, his cycle’s been weird and irregular. Shoko tells him it should eventually stop entirely, but evidently he’s not quite there yet, because the blood-soaked gusset of his underwear glares up at him when he strips off his sweats to check.
Yuuta crawls out of bed just long enough to grab an old towel and drape it over his sheets, because it’s one in the fucking morning and he has nowhere near enough energy to go change and put a pad on. Then he slumps back on his bed with a grunt, already bemoaning the laundry he’ll have to do in the morning.
As if agreeing with him, his gut throbs unpleasantly.
“Yuuuuuuutaaaaaa?”
He winces, because Rika must’ve sensed his distress. Shit.
“‘M’fine,” he mumbles, as the shadows on the walls of his dorm shift and swirl unnaturally. “Go back to sleep, love, my stomach just hurts.”
This does the opposite of deterring her. Rika’s body coalesces out of the darkness; she’s hulking mass of slick, snake-like scales and vicious claws and teeth, massive and frighteningly powerful even when she’s only partially manifested. She doesn’t scare Yuuta, though, as she whimpers anxiously and coils her body around his. Her embrace is gentle, much gentler than her fangs might suggest.
“Stomach hurts?!” Rika warbles, butting her face against his thighs and snuffling loudly. “Sick? Are you sick, Yuuta? I smell blood. Are you hurt? Hurt where?”
Yuuta laughs weakly. Her skin is cool and smooth against his palms, like some kind of marine creature. “I’m not sick, baby. Not hurt, either.”
Rika whines, and rakes her claws agitatedly across his sheets. “But I smell—“
“I’m not hurt,” Yuuta soothes her, pushing her back just enough to slide his shirt over his head. “See? No wounds. I’m just on my period.”
Rika, unconvinced, noses his body, and Yuuta giggles as she flicks out her massive tongue, licking the sleep-sweat off his skin. When she doesn’t find any injuries, she growls in discontent.
“But it hurts,” she mutters. “You said it hurts.”
“Yeah,” Yuuta sighs, wincing as his gut gives another dull pang. “Reversed cursed energy doesn’t really work on it since my body’s not technically damaged. Not much I can do.”
Rika growls, shoving her face into his stomach. “Bullshit.”
Yuuta almost chokes as he laughs in surprise, because Rika rarely swears. “Who taught you that?”
“Toge-senpai.”
“That tracks,” Yuuta sighs.
They lay like that together for a while, Yuuta on his back with Rika resting her chin on his stomach. Her head is a soothing, grounding weight on him, and her rumbling purrs help to dull the pain. Yuuta’s starting to drift off when he feels needlepricks of pain in his upper legs, and he winces, looking down.
He chuckles quietly. Rika’s huge hands are kneading the fat of his thighs, like a cat making biscuits. “Ow. Careful, baby. Claws.”
Rika grunts out an apology, nuzzling further into his stomach, and—oh, fuck.
Her chin bumps against his crotch, and the sticky fabric of his boxers drags against Yuuta’s clit, which is already sensitive thanks to his testosterone injections. Right now, everything between his legs is much wetter and blood-swollen than usual (damn ovulation) and the faintest hint of pressure sends electric shocks up Yuuta’s spine.
He gasps, clapping a hand over his mouth as his hips jerk involuntarily. Rika freezes, and her purring stops. “Yuuuuuuuta?”
“I’m okay,” Yuuta blurts breathily.
There’s a pregnant pause as Rika stares at him, deliberating. Then her tongue lolls out, resting heavy across his chest and stomach in a puddle of saliva—it’s maybe a meter long and several centimeters across at its widest, smooth and fully prehensile. It reminds Yuuta of the monsters from those American superhero comic books he’d read growing up. Looking back, the amount of time he spent staring at those monstrous, many-toothed and tentacled creatures instead of the heroes fighting them definitely wasn’t purely out of innocent fascination.
Yuuta loves every inch of Rika’s pale, scaled and enormous muscular body, every massive claw and fang that could gore him in an instant. She’s beautiful in her monstrousness. Sexy, even.
“Go ahead,” he breathes.
Rika snarls, and shoves her face between his legs.
Now, to say Yuuta’s never done anything like this would be a bold-faced lie—he’s had Rika’s tongue inside all of his holes more times than he can count, and every time it’s bliss. He’s tried using dildos and other sex toys, but they’re never the same; none of them fill him like Rika does, or have the warmth and the scintillating twitches of movement that comes when her tongue stretches him out and bullies its way deep inside. She leaves him sore and aching, and sure, the marks left over and the way he walks funny for days afterwards draw some weird looks from his classmates, but Yuuta loves it. As he likes to joke with Toge, Rika has ruined him for anyone else.
(While Yuuta’s… ah, proclivities towards curses are a popular tidbit of gossip to pass around the Jujutsu Tech campus, Toge’s the only one who has definitive proof. He’d accidentally walked in on them once; Yuuta had been sobbing and face-down on his mattress, while Rika held him down and pounded his cunt open from behind. Instead of freaking out, though, Toge had stayed, undoing his belt with wide, hungry eyes as he gestured for them to continue.
Afterwards, he’d promised not to tell a soul, as long as they didn’t, either. They’ve had a friends-with-benefits arrangement ever since, and Yuuta enjoys it greatly.)
He’s never tried doing anything while he’s on his period, though. Yuuta’s already made up his mind that he needs to remedy this.
“Fuck, fuckfuckfuck,” he whines, his toes curling into the sheets as Rika pries his legs open, pinning them effortlessly. Her tongue is a hot, heavy weight against his swollen, oversensitive cunt, and her teeth shred the fabric of his boxers effortlessly—oh well, they were soaked through with blood anyway. Rika’s breath washes over his stomach as she growls and laps at him like she’s starving, drenching him in globs of saliva. Blood coats her teeth when she leans up to lick the drool off his thighs, and the sight of carmine smeared across her pale, scaled skin makes Yuuta moan.
“Yuuuuttttaaaaaaaaaaaa,” she purrs, and her blood-streaked tongue darts across her lips. “Tastes so gooooooooood.”
Yuuta squirms, gasping as she teases him with lazy, unhurried kitten-licks over his clit. Holy hell, everything just feels so much more right now. “Oh, fuck. Fuck, Rika baby please—“
Rika preens. “My Yuuuuuuta. My pretty boy.”
With that, she pushes the tip of her tongue into him. It’s easily as big as two of Yuuta’s fingers, and he lets out a cry, frantically humping Rika’s face. She starts slow, like she always does, with murmured praise and reassurance, but the further in she thrusts, the more her restraint starts to slip. It’s clear that the taste of his blood is doing something to her, and she wants to be rough.
Yuuta likes it when she’s rough with him. He really likes it.
“Yummy,” Rika mutters, slurping loudly as she fucks her tongue in deeper. Yuuta can practically feel her in his throat already, and he’s shaking, moaning as he drools into his pillow. “Pretty boy. My pretty, yummy boy. More?”
“More,” Yuuta sobs. “More more more, harder, please.”
She growls, folds him in half with her enormous hands, and fucks him faster. Yuuta’s eyes roll back when he presses an unsteady hand against his stomach, and feels for the bulge of her tongue— fuck, there it is. It’s like she’s fucking past his cervix and all the way into his womb, licking, sucking, moaning as she devours him.
Blood, slick, and spit squelches messily as Yuuta manages to shove his hand down to jerk his swollen clit. He cums almost instantly with a muffled wail, and he fucking squirts, too—or pisses himself; he’s not sure which but he’s too far gone to care—thrashing hard against Rika’s iron grip.
She doesn’t let up. She makes a noise like a wounded animal and slurps up every drop of blood and fluid she can reach. Yuuta’s barely conscious by the time she relents, purring and kneading his thighs again as she settles.
He groans sleepily. Rika’s tongue’s still deep inside him, twitching and impossibly huge, and he can feel the girth of it when he moves—see it, too, if he focuses his gaze. The bulge in his stomach is unyielding, big enough that when he so much as shifts his weight it makes him gasp. Best of all, the ache in his gut has lessened considerably, and the way Rika’s tongue subtly undulates and strokes his insides seems to be keeping it at bay.
“Nngh,” Yuuta whines. He’s so warm, so full. Also really fucking tired. “Wanna stay like this.”
Rika growls contentedly. “Love you, Yuuuuutaaaa.”
Yuuta smiles. “Love you too, baby. So much.”
———
He’s so fucking gross and sticky in the morning.
Maki rolls her eyes when he complains to her, when they end up in the campus laundromat at the same time. “See, this is why I get up and change my sheets right away when it happens. Bloodstains are annoying as shit when they’re dried in.”
“But I was tired,” Yuuta groans, furiously scrubbing at one of the stains on his sheets with a Tide pen. “You don’t have insomnia. Plus, you’re a morning person. Your opinion doesn’t count.”
“Shove it, Sergeant Sad Eyes,” Maki remarks, as she hoists her laundry basket up onto her hip. “Also, can you be, like, ten decibels quieter while your girlfriend’s banging you? Don’t know if you remember but we share a wall.”
She ambles out of the laundromat, whistling cheerfully. Yuuta, meanwhile, is left choking on his own spit.