Thread by @revereri

nsfw (osaatsu) #miyacestober2022 day 26 • club + summon , underage , atsumu has a pussy , double penetration //

the smoke and dust cleared, and in front of atsumu, hovering above the summoning circle he drew, was—

something who looked very much like atsumu, actually. +

except it was fucking /huge/, had sharp fingernails and teeth, and pointed horns coming out of its head. it was also very naked, and somehow, for some reason, had /two/ fucking dicks.

"uh—" atsumu was at a loss for words. this wasn't meant to happen. +

"hello there, little one," the thing—demon? greeted. "shall we have some fun?" it hooked a finger under atsumu's chin, tilting his head up, the sharp nail digging into his skin. its tongue slithered out, and it resembled a snake's.

atsumu shivered. +

"who are ya, exactly?" atsumu asked, trying to hold himself together despite wanting to piss himself.

the demon considered for a moment. "hm. you can call me samu. i am... how do ya say, your demon counterpart?"

"d-demon counterpart?!" +

atsumu was a very good boy, thank you very much. he did his chores and sure he maybe acted up sometimes during volleyball practice, but that was all just fun and games! why would /he/ have a demon counterpart?

"but enough about me," samu continued. +

"ya called me here for something."

"actually, not really?" atsumu rushed to explain, "i'm in a summoning club at school, though i was kinda dragged into it because of my friend— i don't actually believe in any of it, ya know? +

but we got assigned /homework/ for some reason to try summon somethin', so i tried and... here you are."

for some reason, it made samu grin. "oh, but you /did/ call me specifically. do ya know what i am, little tsumu?" atsumu gulped. "i'm supposed ta represent +

yer deepest desires, i'm supposed ta make yer wish come true."

"a-and what is that?"

"mm, i think ya know the answer." samu moved closer, right up into atsumu's space. atsumu thought he should get away, but he felt frozen to the spot. +

and then the demon tore away his pants. "you've been dreamin' of this, haven't ya," it taunted, running a finger along atsumu's slit. "look at how wet ya are for me," it then pressed the tip of a finger inside, +

before pulling it back out to show atsumu how it glistened with his slick, a trail connecting them before snapping in the middle.

"i-i don't—" atsumu was a virgin, he hadn't even— he couldn't /imagine/—

"oh, but you're forgetting, i'm a version of you. +

and that means i know just what you're thinking, what you've /thought/, and how you've longed to be stuffed in yer virginal holes."

atsumu shook his head. that was grotesque, atsumu was— "no, no! i'm—"

samu cut him off, "why do ya think i've got two of these," +

it wrapped a hand around its two cocks, "sweetheart? it's so i could /fuck/ ya."

atsumu wanted to cry. it wasn't true, it wasn't. he wasn't a whore! except... except, he was so /wet/, and his heart was pounding at the thought, and he really, /really/ +

wanted the demon to take him.

"that's it, tsumu, give in to yer desire!" samu held out a hand and lifted atsumu to his feet. it then turned atsumu around and pressed his back to its chest.

atsumu sniffled, still afraid, but let the demon touch him as it pleased. +

it thrust its fingers inside his pussy, the obscene wet sounds a testament to his horniness. it gathered up the slick he had produced and then moved its fingers to his other hole, his anus. atsumu let out a shout, his asshole wasn't as accomodating as his cunt, +

and despite how wet he felt it wasn't enough to act as lube. but the demon was relentless, fingering him without mercy, alternating between each of atsumu's holes, opening him up and getting him ready for—

samu pressed /both/ of his cocks inside atsumu at once. +

it felt like it was splitting atsumu apart, he felt like he was burning from inside out. before he knew it, atsumu was being lifted up, up, into the air, so samu had full control of his body, sinking him down onto its erections. +

it was so /full/, both atsumu's pussy and ass stretching to accommodate the demon's larger size.

atsumu had never felt anything better in his /life/. his own fingers never even came close to this, this— /hot/ feeling, from his own core to the hot cocks inside him. +

samu began to fuck him properly, both of his cocks moving in and out in tandem, rubbing against all of his erogenous zones. atsumu was out of his mind, experiencing something he never thought possible, whimpering and moaning as the demon +

bounced him on its cocks.

"please," atsumu begged, not knowing /what/ he was asking for. "please, please."

"that's it, baby," the demon's tongue flickered against atsumu's neck. "you're takin' me so well, you were made for this." +

atsumu cried as the demon thrust into him with force, watching as his belly bulged. all of a sudden a mirror appeared before them, and atsumu could see everything—how small he was in comparison to samu, the way its cocks seemed to impale him. +

"there," samu said, looking directly into atsumu's eyes through the mirror, "now you can watch."

it was difficult to choose between watching himself get fucked and closing his eyes and losing himself to the sensation of it. in the end, he alternated between the two. +

he could /feel/ his holes being stretched, but it was something else entirely to actually /see/ it happen. and then— the demon moved one of its hands down to atsumu's front, first to rub his cock through atsumu, and then down to play with his clit. +

it rubbed gentle soothing circles at first, and then pinched at it, making atsumu gasp. it continued to play with atsumu's clit as it fucked him, and soon, it became all too much.

"'m— i'm gonna come," atsumu whispered, not trusting his voice. +

he felt weak, he had no clue how he was going to walk about this.

"i know," samu replied, amping up the rhythm, "come for me, baby boy."

it fucked into atsumu once more, flicking his clit, and made him come with a scream. fluid gushed out of him— +

atsumu was vaguely aware of what it meant, but it'd only happened to his once before.

it covered the mirror in front of them, blurring the view.

"fuck, that was hot," samu groaned hotly into atsumu's ear. moments later, he felt his insides flooded with a warm liquid, +

leaking out of him and onto the floor below. there was so much, atsumu was convinced the demon's ejaculate wasn't normal.

this was confirmed when samu pulled his cocks out, and liquid just /poured/ from his holes. he couldn't believe that was all in him at one point. +

samu gently set atsumu on the floor, amongst all the come and other liquid, but atsumu was too exhausted to care.

"so, how was it, tsumu?"

atsumu was still catching his breath, he didn't think he could speak even if he wanted. +

"good, yeah?" samu was reading all his thoughts. "better than anythin' ya could've ever imagined?"

weakly, atsumu nodded. he could do that, at least.

then, samu knelt next to him, lifting his chin once more, echoing the start of their encounter, +

"well, feel free ta call me back anytime. ya know how ta summon me." it winked, and then blinked out of existence.

"fuck," atsumu swore, chest heaving. had that actually just happened?

// the next day, when the members at the club asked how atsumu's homework went: haha um nothing happened, unfortunately. next time, right? +

weeks later, after atsumu was no longer able to get off like before, feeling too empty and like nothing was enough anymore: fuck u samu!

pregnancy //
months later, after repeat visits from samu, coming inside atsumu every time, noticing his belly swelling: oh fuck.

i also accidentally wrote cummon instead of summon one time but like,, accurate? LOL anyway this was one of the first prompts i planned and was so excited for, so happy to finally write it!!