Thread by @murcielagoAO3

#nsfw #miyacest cw: masturbation, tentacle dildo, anal sex

Atsumu half-jokingly mentions one night that it might be fun to have a monster dildo like a tentacle or something to play around with sometimes.

Osamu knows full well that behind the joke, there's a real desire for kink exploration, and damn if he's not into it too.

He finds the most massive tentacle dildo on the web, and orders a custom one with a deep grey base like an octopus, and a pink fleshy color for the S-curved

and knobby insertible end with faux suckers that get smaller at the tip.

It's monstrous all right. /Obscene./ And oh, the thrill of presenting it in a box to Atsumu, watching him unwrap it and then--eyes bulging--turning bright crimson and stuttering, nervous to even pick it up.

"Here," Osamu takes the box. "Lemme help ya get acquainted."

If Osamu's turned on to the max to watch his brother's pro athlete fingers jerk the thing off, then cover it in his saliva and swallow it down, tears streaming down his face--

Probably doesn't compare to how worked up Atsumu gets, feeling those suckers and knobby bits on his lips and down his throat, surrendering to the sensations. When he's too far gone not to choke, Osamu pulls it out, only for Atsumu to beg for it, tongue out and pupils blown wide.

Osamu rubs the slimy surface over Atsumu's nips and down his abs. Atsumu whines and clings to him, rutting into Osamu's thigh.

"Jeez, fuck," Osamu grunts, wedging the tentacle between their cocks like a three-way frot, rocking into Atsumu who keens and cries desperately to cum.

The knobs and ridges feel so good on his cock, and the silicone has a give to it like real flesh. It's bizarre and the thought of some monster holding their dicks together tight like this is so weirdly hot that Osamu starts to overheat as well.

They both cum quickly, everything so new and strangely heightened, warm jizz all over their hands and the dildo. Atsumu sobs, sucking air to catch his breath. But he wants /more/, turning over and offering his ass, spreading himself for display with his own hand.

"Put it in me, please, Samu," he begs.

Osamu doesn't care what switch got flipped in all this experimentation, he's game to try anything, especially if it means taking his brother apart.

"Hold steady," he warns, getting into a better position behind his brother. There's enough

of their cum all over the damn thing that he can just start working it into Atsumu's hole immediately, pressing the tapered tip to his rim and twisting it slowly inside. Atsumu moans, twitching as it goes in, but he's doing his best to hold his cheeks apart and take it,

so Osamu forces it in further and tells him how good he's doing. He shoves and twists it roughly now and again, getting into character 'cause a real tentacle monster would just wiggle and shove inside without warning. Osamu shivers at the lick of fire that rolls through him,

wishing he had /real/ tentacles to use on Atsumu and could feel the inside of every orifice at once, even down his brother's dick slit, tickling him in places he's never been touched until Atsumu can't scream or cum anymore.

Osamu hurries up with the dildo, biting his lip

as it disappears further and further inside Atsumu's hole. His brother shudders & lets go of his cheek to grip into their bedding, arching back to take more of the tentacle.

"Deeper, hurry," Atsumu groans, bucking back towards Osamu's hand and shaking.

Osamu pulls the tentacle

almost all the way out, making Atsumu cry no-no-no-no as the girth tapers down, then he shoves it back in all the way and Atsumu bucks, shouting open-mouthed in pleasure. Osamu twists it back and forth as he fucks it hard and fast into his brother, lines up the rows of suckers

so they washboard over Atsumu's prostate all the way in and out. Four passes like this and Atsumu comes screaming, body jerking like a live wire.

"Oh fuck, oh fuck," Osamu murmurs on repeat, awestruck by the dildo's effects. Atsumu seems completely fucked out, barely conscious.

"Tsumu?" Osamu asks, brow furrowed and gently tapping Atsumu's cheeks.

Atsumu nuzzles his hand and hums softly, voice hoarse. Osamu exhales in relief, but is unfortunately aware of his still hard dick, pulse beating in his veins.

He reaches for Atsumu's gaping hole, brushing

his thumb across it, then dipping inside. Atsumu inhales then moans and rocks back against him.

"Warm," Atsumu murmurs, beckoning to him.

"Wanna feel ya," Osamu answers, leaning down for a kiss. Atsumu nods, kissing him back though he lacks the energy for their usual kisses.

Osamu shifts Atsumu more comfortably on his tummy and widens his legs before lining up and pushing his cock all the way in. Atsumu writhes, but in the good way, all sexy and feeling it. Osamu starts slow, watching his brother's reactions, then starts to snap his hips harder.

Atsumu's walls are soft and supple but grip him tight, and Osamu groans, dicking him with hard strokes to match what his brother felt from the tentacle. He glances at it on the bed, then has an idea. He stops to wedge a finger into Atsumu along his dick, then picks up the dildo

and pushes the tip of it past Atsumu's rim.

Atsumu gasps, looking over his shoulder, pupils still blown wide. Osamu slides more of the dildo inside, hissing as the rows of suckers scrape pleasantly along his shaft. He rotates it underneath his cock so he can fuck along those

divots, pushing it into Atsumu with every thrust.

Atsumu continues to moan and beg for more until Osamu sees him go tense, brows scrunched. He's at his limits, but it's impressive just how much he's been stretched by the dildo and Osamu's thick cock.

Every time he thrusts,

it feels like he and the monster are fucking Atsumu together. The sickening pleasure of the tentacle's caress along his cock brings him to climax so suddenly Osamu's elbows falter and he ends up collapsed onto his twin's warm, sweaty back, hips jerking uncontrollably and dick

twitching with every hot spurt.

For a long moment he can't move. Atsumu gives a pitiful whine beneath him, helpless and trapped, which knocks Osamu back into motion. He eases off his brother, and then pulls out as gently as possible along with the dildo.

They lie there a while, breathing, maybe crying a little, unable to speak.

Osamu closes his eyes, a smile tugging at his mouth.

Best $200 he's spent in his entire life.

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(Osamu likes to tease Atsumu about packing the dildo when he goes on away games so he's not lonely at night.

Atsumu refuses--what if he uses it and passes out when he comes and /that's/ how the paramedics find him? Or his teammates?! NO WAY.)

Osamu smirks, and has it ready for him when he gets back. It's always the best when they've had to abstain a little, and there's nothing like a good tentacle fuck when you're real hungry.

🍙🏐🐙💖

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