Haikyuu Age Regression One Shots

Baby Brother ( Miya twins )

THIS IS NOT SHIP CONTENT.

request from @cucumber4677
caregiver Osamu, regressor Atsumu

<3
It wasn't really like Atsumu to become overly stressed about things, but lately, he hadn't been in the best place. He wasn't sure what it was, but he felt overwhelmed- he didn't want to get up for classes every morning, and his grades were slipping slightly, which the volleyball coach didn't fail to get on him about. It felt like too much, but he powered through it the best he could, getting through the days and going to bed like normal, usually feeling overly exhausted. Tonight, though, he'd been stressing before he fell asleep, which plunged him into an unfortunate nightmare. One that had him waking up in a cold sweat, gulping in gasps of air as he clutched his chest, his heart beating rapidly. Everything was bleary for a moment, though he slightly got his bearings, his was still quite terrified, his eyes swimming with tears. Doing the only thing he thought to do in his panicked desperation, he shakily crawled down the bunk ladder, not coming down all the way and just hanging onto it. He needed someone. "..Samu." He whisper-yelled. "Samu.. Wake up.." He said a little louder, his voice breaking slightly.

Osamu was on the exact same page as his brother, classes were horrible, he wanted it all to end , he needed a break, and that happened to be the reason as to why he slept so often. Osamu was using rest as his one escapism from the rest of his life, it was his free ticket out of all his troubles as worries. He didn't care about volley ball, but he did care about his grades and possibility of getting into post-secondary. So when he awoke to shuffling and whispers , he was grumpier than he would've meant. " what ?" he groaned out, not realizing that his twin had climbed in bed with him.Atsumu finally stepped down from the bunk ladder, crawling into bed next to Osamu, clenching his jaw a bit and fiddling with his shaky hands when the response he received was thoroughly irritated. "...Uhm..." He said quietly, trying to breathe- trying *not* to cry, even if he really wanted to. "I had a bad dream..." He mumbled, almost trailing off, and it sounded entirely childish of a reason to be waking his twin up in the middle of the night. Though he couldn't really feel ashamed. He sniffled, wiping the wetness from his eyes as he awaited any response from the other, hoping he wouldn't be mad. He felt really small and scared at the moment, and the last thing he needed was to be pushed away, even if he felt as if he was dramatic.

Osamu sat up from where he was laying, tired and looking somewhat irritated as he rubbed his eyes to get the sleep out of them. But when he saw the look on Atsumu's face he was only reminded of ther childhood , how his brother so often found himself in horrible distress throughout the night in their younger years. " It's fine .. you can talk to me.." He sighed out as he brushed his hair back with his hand. " You know i'm here..." he groaned before hugging his brother tightly.Atsumu felt at least some of the weight lift from his chest when he realized Osamu wouldn't be angry with him, and he returned the hug he was given, a little sob escaping him as he did, "K-Kicked me out of volleyball 'cause- 'cause... Wasn't smart... B-Bad grades and- and my whole life is gon' be *over*..." He rambled, trying to explain his nightmare, though some of it just mixed with his real life worries. His breath heaved and he could really stay all that calm, incredibly worked up and not entirely in his right mind, burying his face against Osamu's shoulder and holding tightly onto his twin's shirt.

Osamu tiredly wrapped his arms around Atsumu, patting his back gently as he could to try and soothe the other. " It was just a dream.." he minutes , trying his best to calm his twin. " But why are ya baby talking ? Ya sound like you're tryna be all cute." he said as more of a statement, more so than any of his comforting was.Atsumu felt himself freeze up, immediately quieting as his tears ceased in favor of being embarrassed. He hadn't even realized he'd been talking like that, he was so distressed it totally slipped his mind not to completely go into his headspace that he used to cope- one that no one knew about, not even Osamu, who pretty much knew everything about him. "Uhm- uh..." He struggled to find an explanation, his brain feeling foggy, and he momentarily wondered if he should just tell him. Though he worried that might be humiliating. "Nothin'. Leave me alone 'bout it." He huffed, trying to be defensive. Osamu rolled his eyes gently as he held his brother tighter, noticing that the tone of voice hadn't changed and that his twin had gone bright red. Patting his back gently he sighed, taking a long breath of air. " you can tell me whatever ... you know that.." he
explained quietly, wanting the other to be able to feel open and honest.

Of course Atsumu knew that was true- he'd Osamu everything, even when the other didn't particularly want to know, for his entire life. He wasn't sure why this was different, but he felt as if it was. Maybe it was the raw vulnerability of it? He couldn't really think hard enough to figure it out in the moment. "...You're gonna make fun of me." He said decidedly, his voice slurred, and he sounded very identical to a pouting toddler, which he wasn't much more than. Osamu rolled his eyes and gave a little pat to Atsumu's back in a joking sort of way. " i'm not going to make fun of you. I never do unless you're being a dork. If it's that serious I couldn't do that.." he said with full honesty, looking his brother in his eyes to communicate his truth. Atsumu sniffled and hiccuped, searching Osamu's gaze for any inkling of doubt or lies, but he found nothing, his brows creasing slightly as he averted his gaze. "I just... Sometimes I feel real small when m'stressed an' stuff..." He tried to explain in an embarrassed sort of mumble, "Like I'm a lil kid again... An' I think like one..." He was almost whispering, now, and he suddenly he began scrambling off the bed like he was going back up to his own. "M'sorry, goodnight.." He squeaked out, thoroughly embarrassed.

Osamu rolled his eyes and pulled Atsumu into a tight hug, seeming almost as if he never wanted to let go with the firm grip he had. " cmon don't say sorry, i'm glad to have a little brother." he said the last part almost teasingly , trying to get a reaction from his brother who he had pulled in.
Atsumu's lip wobbled and he sighed a breath of relief that Osamu wasn't completely disregarding him or even making fun of him- that he was actually being supportive. "...I's weird, though..." He sniffled, feeling a bit insecure since he'd never really told anyone about this part of him before. It felt like it would always be a secret he'd have to keep. Hiccuping softly, he slipped his thumb into his mouth to soothe himself without really realizing it.

Osamu shook his head , rubbing up and down on Atsumu's back. Though he didn't know about this until today, he always knew Atsumu was more immature , making him take more of an older brother role no matter what the occasion. " shut up dummie, you're not weird. You're allowed to relax.." he groaned , acting more tired than he actually was.Atsumu nodded hesitantly, not having expected the support, but not being entirely surprised by it either. Osamu was never mean to him when it genuinely mattered- he was an amazing brother, they just bickered more often than not, as siblings do. "...'Kay..." He slurred around his thumb, "Samu can make sure m'safe? From bad dreams..? An' bad things..?" He questioned softly, immediately latching onto Osamu as a figure of support to rely on in his small state. Osamu leaned back on the bed , keeping his arm around Atsumu so they were lying beside one another. It was a good thing that osamu placed glow in the dark stars under Atsumu's bunk so stare at it as he fell asleep." see those ? Those keep my dreams safe . They'll keep yours safe too if you sleep under here.." he whispered , using a way of comforting their mother previously had.

Atsumu's eyes looked up at the plastic stars curiously, almost noticing them for the first time as he latched onto Osamu's side. He rubbed at his eye with his hand that wasn't in his mouth, feeling comforted by the words that were spoken to him. He gave a small nod, his eyes falling shut even though he fought to keep them open. It was still late in the night, though, so he should really be falling back asleep, even if it was the weekend. "...Doggie's gonna be lonely in my bed all by his self..." He murmured sadly after a moment of thinking, referring to his fox plushie that he'd had since he was a baby that he still slept with every night.Osamu nodded singularly before crawling up for just a moment, grabbing the plush with a quick swipe before handing it to his brother who clearly wasn't at his normal headspace. " Doggie's not alone anymore, don't worry bud..." he sighed , not minding that the other was regressing, but still having been quite tired since it was so late at night.

Osamu pulled the blanket over the both of them, tucking in his twin before brushing the blonde hair out of the others face and turning in the opposite direction. " night little dude.." he whispered before letting himself drift off just the same.