Thread by @justsayins

@disloyalpunk was going around bringing up sheith + fisting and I had An Idea, so here, have a thread.

Uh. contains, basically that ^

hc for this is that Keith is relatively inexperienced before he and Shiro happen, at least in terms of kink. Shiro is def the first person he doesn't mind--WANTS to feel vulnerable with, so that introduces a lot of possibilities he's never actually thought of before.

& he doesn’t know there’s a NAME for it or anything. it’s just one night when they’re together. Keith had sucked Shiro off, then Shiro’s eyes had glinted and he’d moved to press Keith down. fingering him until he’s sloppy with lube. the eventual goal is to make Keith come but

right now Shiro’s focus on just making Keith writhe and beg. he’s using his human hand, but even then two fingers are really all Shiro needs. still, tucking in a third makes Keith keen once they work up to that. Keith’s always liked being full and he’s been pretty vocal about it

(something that Shiro 1. likes and 2. is kind of relieved by, b/c Shiro’s pretty big and it’s something he’s had worry about before) and Keith is also SO weak for Shiro’s voice and dirty talk. Shiro presses a kiss to one of the dimples in Keith’s back, feeling him shake

“Like that, baby? Being full up?” Keith lets out a broken moan and Shiro grins against his skin, keeps going, murmurs, “I bet I could add another finger. Give you four. You’d take it so well. God, I’d keep going until you cried--” and Keith’s pretty much on his way there anyway

squirming underneath Shiro, his hands clutching the sheets. Shiro’s fingers are as big as the rest of him and sex in general with Shiro is just--everything Keith ever wanted, but being opened up by him like this, Shiro working him, fucking Keith on his fingers, calluses rubbing

“please,” Keith begs, “please, yeah, I can take it, please--” it’s been a while of this, so Shiro is pretty sure this is mostly Keith losing his mind. 4 fingers would be a LOT and more than Keith’s ever taken before. but he can’t pretend he doesn’t find the idea ridiculously hot.

“Yeah? You think of can take four of my fingers? You want to be filled like that? This-” he drags the callused pads of his fingers right over Keith’s prostate again “-isn’t enough?” Keith gasps, gasps again when Shiro keeps going. “Bet you could take my whole hand.”

Keith’s reaction sends a jolt of arousal through Shiro. “Like that idea, baby?” he’s surprised his own voice doesn’t shake, but maybe that’s b/c it’s so low now it’s practically a growl. “My whole fist inside of you?” and that’s it, Keith is coming with a sob.

& Keith THINKS about it. a lot. about what it would be like, feel like. taking Shiro’s fist. Fuck it’d be--the thought makes him shiver. Being that open for Shiro, taking that much of him. being that vulnerable with the person he trusts the most in the universe.

“could you?” he asks one day, when they’re curled up together. Sleepy & sated, & Keith figures nows a good a time as any. it’s not something he’d want to spring on Shiro in the /middle/ of sex, since he figures Shiro’d kind of maybe need convincing outside of heat of the moment.

he really, really wants to make this happen so he wants to lessen the chances of Shiro balking and saying no. “Could I what?” Shiro asks. Keith swallows, nervous all of a sudden. is it weird to want something like that this much? Will Shiro find it weird?

he’d teased about it, but it might’ve simply been dirty talk. heat of the moment. but of course Shiro can feel him getting all uncertain. “Keith?” Shiro kisses his shoulder. “Could I what? You can always ask for what you want.”

Right. Keith’s still not used to that. Shiro might say no, but it won’t come with disdain or ridicule. “I want you in me,” Keith says eventually. Shiro, b/c he’s amazing, manages to pick up that this is a serious question, so he doesn’t tease about the fact he was just in Keith.

Keith goes on. “Your fingers. When you--I want all of you. Like you said before.” fuck fuck fuck, why is this hard to ask for? he doesn’t have trouble talking about sex. or he DID, back when he still couldn’t believe he got to have Shiro at all but he thought he’d gotten over it.

At least Shiro is SHIRO. Meaning he somehow understands. “You want my whole hand?” thank god he doesn’t sound incredulous, b/c if he did Keith is pretty sure he’d die. “Yeah,” Keith manages. even talking about him makes him feel shaky.

on Shiro’s end, Shiro is trying to tamp down how BLINDINGLY HOT he finds the very idea of opening Keith up like that and filling him that full. having Keith take that much of him--Keith /wanting/ it.

part of that is Shiro being ever aware of how much Keith keeps close to his chest and how he protects himself. Keith’s trust is something Shiro still can’t believe he earned and something he never wants to take advantage of.

this is an extension of that trust. this is Keith asking for, yeah, something that he thinks will feel good, but it’s also another way to be physically and emotionally vulnerable and Shiro gets that. Gets maybe that it’s one of the reasons Keith’s so hesitant to ask.

(of course, he’s also dying to feel Keith around him. to take Keith apart in a new way. god, he’d feel so good, and Shiro can already imagine him shaking to pieces, clenching around him, Keith’s moans going breathy–)

Shiro can’t help it, he reaches for Keith, pulls him into a searing kiss. Keith makes a noise of surprise into his mouth but returns it enthusiastically. “Yeah,” Shiro says when they part, voice low and heated. “I think that’s something we can do.”

It’s something they literally have to schedule; they’re both busy, and not only do they want time for the actual night, but Shiro insists they pick a day where Keith has the next day free too. Keith rolls his eyes over that--

up until Shiro gives Keith a heated look & drags him down into his lap. “You’re going to want the recovery time,” Shiro murmurs into his ear, hands starting to roam, “because I’m going to wreck you.”

(Keith did not realize just how into this Shiro would be but he is /really/ not complaining. It’s something that’s riling them both up, something they’re looking forward, and a new thing for them to tease each other with.)

they’re both basically useless on the day in question. when they’re finally done with obligations for the day, the mood immediately turns hot & playful. they share the shower first & then part ways to each finish getting ready.

Shiro lays Keith down onto his back & they spend long moments just kissing, trailing their hands over each others’ bodies. eventually Keith starts to make needy little noises against Shiro’s mouth--he’s been wound up, after all

(Shiro has been too, but he is definitely more capable of patience.) They work up to the first two fingers easily, a slow glide that has Keith whimpering, legs spreading even more open. Shiro pets his thigh with his right hand, left hand still working, still moving inside him

At four fingers Keith is a trembling mess, letting out high-pitched little moans, “yes, yes, yes” whenever Shiro asks him if he’s alright, if he’s okay to keep going, if it feels good. “please,” Keith gasps after even more of this, “please, I’m ready, please”

Shiro takes a shaky breath and withdraws his fingers, hushing Keith when he cries at the loss. “Almost there, baby.” he coats his fingers with even more lube and presses his thumb in against his four fingers before beginning to press back in. “Relax for me, sweetheart.”

Keith whines, does his best to melt into the mattress, as Shiro lets his hand be pulled in. “oh f-fuck,” Keith breathes after a long quiet moment. “oh fuck, /Sh-Shiro/ I--” he shifts just a little “/hn/”

“You okay, baby?” Shiro asks. It’s almost a whisper. He’s staring open-mouthed at his hand swallowed to the wrist, Keith pink and stretched around him. He swallows, looks to Keith’s face to take in his expression. “Talk to me.”

“F-feels good.” Keith is trembling. “Feels--god, feels so full, Shiro. Fuck, ah--” Keith clenches around Shiro’s fist and it draws out a moan from both of them. It’s /intimate/ is what it feels like, on both sides.

Once Keith gives the go-ahead, Shiro experimentally starts to move his hand. twisting it inside, and Keith is so soft, so hot, moaning as he tosses his head, hair spilling across the pillow, and this is a new way to devour every inch of him. Shiro /loves/ it.

Keith does too, chanting Shiro’s name, and when he arches up and clenches around Shiro’s fist it’s--god, it’s beautiful. Shiro takes himself in hand and follows Keith over the edge and they’re both winded, trembling

Shiro carefully slides his hand out and Keith sighs, boneless. He takes a minute, then presses a kiss to the inside of Keith’s thigh. “Be right back.” he cleans up, comes back with a warm, wet towel to wipe the come off Keith’s stomach, the lube trickling out of Keith’s hole

Can’t help but stare at the pucker, pink and puffy, open in a way it’s never been before. Smooths his hands down Keith’s thighs and thumbs a little at the rim. Keith whimpers and manages to push himself up on his elbows to look at Shiro between his legs.

Shiro grins up at him and crawls up the length of Keith’s body. Wraps his arms around him and pulls him close, pushes some hair out of his eyes and then takes his mouth. Keith goes easily, lax in Shiro’s arm, totally content.

“Good?” Shiro asks. Keith nods muzzily. “Fuck yeah,” he mumbles, pressing in closer, tucking his face into Shiro’s neck. “Gonna feel this tomorrow.” Shiro chuckles. “S’why I told you you’d want the day free.”

“Mm. Like it. Like when I can feel you.” Shiro can’t help the curl of pleasure at that. He strokes Keith’s back, murmurs, “thank you” into Keith’s hair, who pulls back just enough to blink at him, sleepy and confused. “For what?”

“Trusting me with this,” Shiro replies, kissing Keith’s forehead. Keith snorts and presses his face back into Shiro’s neck. “Always trust you.” and Shiro breathes out a sigh, because god he loves this man and he is so, so lucky to have him.

Fin.

Honestly I feel like I should have gone with THE END b/c that's how I feel about this monster of a thread.