Kirishima and Bakugou going separate ways after UA. After a few months Kiri is like fuck this and goes to visit Bakugou and confess. Kiri tells people he's going away for a bit and isn't sure when he'll be back (if Baku says no he'll need some time to recover)

Kiri doesn't tell Bakugou he's coming, he wants it to be a surprise.

He's almost at the blond's apartment when a kid bumps into him and turns him into a dog.

It was an accident, Kiri wasn't upset, but the kid freaked out and bolted so th a red head is kinda stuck.

He decides to go with his original plan to see Bakugou, but know he has to get the blond to help with this quirk first.

Bakugou's out for a jog when Kirishima spots him, so he runs and keeps pace, explaining the situation. His words come out as snorts, chirps and barks.

To Kirishima's surprise Bakugou looks around before squatting down to pet him.

"No collar..." he mumbles "always wanted a dog"

Bakugou picks Kiri up (and he us /not/ a small dog) and takes him back to his apartment. If the red head could blush he would have.

Kiri tries to tell Bakugou he's the dog, he really does, but it's hard to focus when his crush is just lounging naked in the apartment. He never realized the blond liked just being naked like that.

It sucks when Bakugou takes him to the vet a couple weeks later.

They give him a ton of shots, which couldn't be good for him, and then Bakugou gets him chipped. //chipped//.

This is gonna be awkward to explain when Kiri changes back. He just hopes Bakugou doesn't decide to get him neutered.

2 months later Kirishima is starting to wonder if he'll change back. He s fallen into the roll of Bakugou's dog and he kinda likes it. Sure he misses a bunch of things, mostly having thumbs and talking, but he loves this new side of Bakugou only he gets to see.

Another month passes and Bakugou comes home visibly distressed while yelling into the phone.

"You haven't had /any/ contact? Why are you just now telling me this??" Bakugou slams the door and kicks off his boots "he didn't say where he was going? Not even a hint?"

He flips to speaker and tosses his cracked phone into the counter.

"Nah, dude, I told you everything I know!" Kiri's ears perked up. It was Tetsutetsu. "He said he has some thing important to take care of and that he might be gone for awhile. I was hoping you had seen him"

"No I haven't seen him" Bakugou rubbed his face and groans "the last time I talked to him was four months ago"

Oh they were talking about him. Kirishima whined and rubs Bakugou's thigh with his cheek.

"Go through his bank records, he might have used his credit card"

Oops, Kiri had bought his train tickets with cash.

"Already tried, bro"

"Then I'll talk to the police to get security footage from the train stations. I'll find that shitty haired idiot"

"Thanks Bakugou"

The blond let's out a shaky breath after Tetsu hangs up "God damn it"

Bakugou starts spending all his time looking for Kirishima and it makes the red head feel extremely guilty.

Around the same time the quirk starts to fade, very slowly.

It's so slow that Kirishima doesn't notice at first. His vision steadily starts to return to normal.

Same with his sense of smell, which is disorienting.

He also starts losing his fur which causes Bakugou to worry even more.

"I got enough shit to worry about..." Bakugou grumbles, brushing through Kirishima's patchy coat.

After a particularly bad day Bakugou goes to bed early and calls Kirishima In to the bed with him. The blond rarely let Kirishima onto the furniture, especially his own bed. Bakugou threw an arm over Kirishima and fell asleep.

That night Kirishima changed.

He didn't go all the way back, he still had paws, a tail, dog ears and fur, but he was clearly Kirishima.

He woke up to Bakugou's scream.

Kirishima shot up, their foreheads colliding, and the red head fell off the bed with a groan.

"Kirishima??"

He looked up at Bakugou's shocked face and started crying. He tried to say 'yes it's me!' But all that came out was a bark.

"You... What... You..." Bakugou stammered before turning red and wrapped the blanket around his lower half "You were my dog this whole time?!"

Kirishima nodded and blushed, using his paws to cover himself as best he could.

Bakugou was cursing, flip flopping between happy relief, anger, and embarrassment.

"Of course you were the dog. Fuck you acted exactly the same as you always do I'm so stupid"

Kiri nodded slowly.

"You saw me naked" Bakugou groaned.

He nodded again.

"You saw me jerk off" the blond flipped back obto the bed.

Kiri blushed.

"You humped my leg that one time!"

Kirishima flushed a deeper red and looked away. Yeah he wasn't proud of that.

In his defense it was really hard to get off with no porn and no hands.

"Why were you even over here? You live almost 5 hours away"

Kirishima whined. He really wish he could talk again.

"Kirishima" Bakugou was on the floor with him now, the sheet loosely around his hips, half on the bed still "I'm glad you're alright"

The red head sucked in a breath, looking at Bakugou with teary wide eyes. He put a paw awkwardly on the blond's cheek as the other man leaned in

Then Kirishima licked Bakugou's face, wet and sloppy over his lips.

Oops.

The blond recoiled, "What the fuck Kirishima! You're not a dog anymore!"

Yeah, tell that to his other head.

Kirishima growled and leaned into Bakugou's space, teeth grazing his jaw. The blond gasped, letting his head fall to the side as Kiri started nipping and licking his skin.

"Horny mutt" Bakugou groaned.

The red head wasn't listening. His brain was still a little messed up from being a dog for so long, plus he hadn't properly gotten off in almost 8 months. He was only so strong.

Kiri crawling closer, forcing the blond to lean back until he fell over.

A thin layer of cotton was the only thing between them as Kiri rubbed his hard on against Bakugou's hip. He growled and panted in to the blond's ear, claws digging into the carpet.

"Mo... Re..." Kirishima rumbled, the syllabus felt alien on his tongue.

Bakugou flushed but didn't move. Kirishima growled, using his face and shoulder to flip the blond over himself.

"Hey! W-wait!"

The red head held him down with his body weight, his chest flush against Bakugou's toned back as he slid his cock between his cheeks, moaning loudly.

((Oops uh cw: dub con, rough sex, top Kiri, breed kink? Idk))

Kiri felt like his head was spinning, primal animalistic desire screaming at him to breed. He wanted it so badly, he had wanted it the entire time he was a dog. It was miracle he only humped Bakugou's leg once.

He sunk his teeth into Bakugou's shoulder and the blond shuddered and moaned, hips pushed back against him.

/yes/. Bakugou wanted him too.

He picked up the pace, snarling against the blond's skin, inhaling his sweet scent.

He flexed his paws against the ground a few times until he felt his thumbs return. Finally. Kirishima grabbed onto Bakugou's hips and pulled him up into his hands and knees, claws piercing soft skin and causing him to cry out.

"K-Kirishima!"

"Br... Eed..." Kirishima huffed, dropping Bakugou's hips to spread him open "m...ine..."

Bakugou went stuff before twisting away "Wait you damn mutt!"

Kirishima growled threateningly, lunging on top of the blond again and forcing him down.

"Breed" he repeated

Bakugou set of a small explosion to push Kirishima off and then grabbed the bedside drawer, dumping the contents onto the floor. The red head grabbed at Bakugou's leg"

"No. Stay" Bakugou hissed.

Kirishima whined but, to the blond's surprised, backed off

He smirked and got back into his hand and knees, coating his fingers with lube before making a show of working a single one inside. Kiri whimpered, Bakugou could hear him shuffle closer.

"Bad boy. Stay" he said firmly, groaning as he pushed another finger along side the first.

It had been awhile since Bakugou had done this and he was rushing.

After a few moments Kiri began to cautiously approach again.

"Sta-AY~" Bakugou gasped as he felt the red head's tongue lick around his fingers, hot and wet.

Claws dug in to his thighs, pulling him closer

"Fuck!" The blond groaned, forcing in a third finger "fuck don't stop"

Kiri growled, rocking the blond back on his tongue, trying to force himself in along side his fingers. He was anything but gentle, teeth scraping sensitive skin, tongue prodding at Bakugou's entrance and sliding between his fingers.

He defiantly still had a dog tongue. Weird.

The red head nipped at Bakugou's hand until he got the hint and moved, his fingers being replaced by Kirishima's eager tongue in seconds. Bakugou moaned, clenchind down on the muscle as it pushed inside.

It wasn't enough, the blond needed more.

"Kirishima, fuck!"

Bakugou whined, hating how needy he sounded.

Kirishima groaned, moving his tongue faster, slobber pouring out the sides of his mouth and down Bakugou's taint. It was so wet, the red head was making slurping noises as he ate him out.

"Just fuck me!" Bakugou gasped, hands boring the carpet.

Kiri snarled, sinking his teeth into the blond's ass cheek before shoving him down onto his stomach. His hand fell on the back of Bakugou's neck holding him down as pressed against the blond's stretched, spit slick hole.

"Breed" Kirishima rumbled, his voice low and raspy.

Bakugou shuddered, holding his breath as the red head pushed forwards.

((I'll be back in a little I promise))

Bakugou was woefully unprepared for just how thick Kirishima was.

The tip popped inside and punched the air out of Bakugou's lungs, his body clamped down on the intrusion, hands smoking as his jaw dropped in a silent scream.

It tore a roar from Kirishima's lips, the red head's hips trembled as the sliver of self control he had left kept him from slamming all the way to the hint. Bakugou felt good, so so good.

"Hot" Kirishima gasped, his hold on the back of Bakugou's neck tightened as he cursed.

The red head sunk his cock in slowly, inch by agonizing inch , he seem to stretch on forever. Bakugou groaned when it hit the back, he felt so full. He couldn't take anymore.

Kirishima wrapped his clawed hands around the blond's waist and forced him back the rest if the way.

Bakugou choked on a scream, the noise drowned out by Kirishima's pleasured moan.

"Tight, you're so tight Bakugou" he gasped, voice finally working right.

Kiri pulled back about halfway and slammed back in, skin slapping loudly against skin.

The blond couldn't respond, drool leaking out of his slack mouth, his eyes blown wide but uneeing as he was impaled repeatedly on Kirishima's length. This was nothing like how he imagined it would be, Bakugou had always pictured himself on top.

He also didn't picture Kirishima as a dog but you know...

It steadily became easier as his body adjusted and Bakugou was finally able to push back into Kirishima's thrusts, moaning each time the red head bottomed out and his heavy balls hit his taint.

"I wanna fill you up, Bakugou" Kirishima growled, planting his hands on either side of the blond's head and going impossibly faster "wanna breed you"

Bakugou whimpered and it started to feel tight again, something kept catching when Kirishima pulled out.

"Kirishima" he moaned

"Gonna knot you. Breed you. Make you round with my pups"

Knot?

Kiri sat back up, grabbing Bakugou's firearms and pulling them back, lifting his chest off the ground. The blond groaned, his head falling forwards, eyes half open and blurry with tears, hair matted to his forehead with sweat.

When Kirishima tried to thrust back in something big stopped him from going all the way in. The red head groan in frustration, grinding it against Bakugou's entrance.

"/please/" Kirishima whined, pulling Bakugou's arms so hard the blond worried they might pop out of socket

"Pleasepleaseplease let me! Master I've been good! A good boy! PLEASE!"

/oh fuck/

Bakugou had referred to himself as master couple of times when Kirishima was his dog.

Bakugou groaned, and pushed his hips weakly.

The knot popped inside and Bakugou's body went stiff, stars flashing behind his eyes as it settled against his prostate. Kirishima continued to roll his hips, pressing deeper until he came with a shout, flooding Bakugou's insides with cum.

It's the first time Bakugou ever /felt/ someone cumming inside him and he groaned at the feeling.

Kiri let go of his arms wrapping one arm around Bakugou's chest and grabbing the blond's neglected cock. It only took a few quick strokes for him to spill into kiri's hands.

They collapsed, breathing heavily and covered in sweat, locked together by Kirishima's knot.

Everything else, except the knot, returned to normal a few minutes later.

Kirishima apologized over and over for jumping Bakugou.

"It's fucking you asshole. How long until this thing goes down?"

"I don't know! I've never had a knot before!"

"Fucking hell..."

There was a brief pause.

"Can we order food?"

"Jesus christ, Kirishima, your dick is still 9 inches up my ass!"

"But I haven't had anything but dog food for months!"

Bakugou scowled "I got you the good stuff"

"Yeah but I want real food..."

"Fine. Once this thing goes away we can get lunch."

"Ok... And Bakugou?"

"Yeah?"

"I... I've been in love with you for years."

"Yeah no shit" Kirishima bit his lip and Bakugou rolled his eyes, craning his neck so he could look at his idiot "I love you too, stupid mutt"

The end