Katsuki Bakugo is callused palms, untidy hair, and an explosive temper, but he is also a perfectionist. As much as he might want to value being ‘cool,’ he values being the perfect budding hero more. Yelling at his friends like their mother, nagging them not to smoke, so that he wouldn’t get dragged into it.
He didn’t struggle for anything, always has extra spending money and gets enough to eat, enough exercise, he gets nearly perfect grades. What he does miss out on sometimes is sleep, and it is infuriating. Sleep is essential to peak performance, and when left to his own devices he just can’t seem to fall asleep or stay asleep.
As a baby even, his parents would sometimes have to drape a blanket or rag over his eyes while they rocked him to sleep. Any light would be overstimulating and keep him up. As he grew into a toddler he found unexpected relief when he had his first sleepover with the neighbor boy, Izuku. When Katsuki’s parents learn that sleeping in a pile with the boy a few houses down means he sleeps the whole night through they spend virtually every night together at one of their houses.
This goes on and despite whatever arguments go on during daylight hours, they fall asleep draped over each other. It’s not until they’re nearly to middle school before they start to distance themselves from each other even while at home. By middle school they spend most nights alone, but every so often, when the bags under Kacchan’s eyes get bad enough, he lets himself into the Midoriya’s home and crawls into Deku’s bed. Out of habit, Deku scoots over to make room without even waking up all the way. He never seems surprised or upset when he wakes up crowded in his own single person bed, just rubs the sleep from his eyes and nudges Kacchan awake so he has time to get ready properly. On these mornings Kacchan is the same boy he ever was, bleary-eyed and sleep-sweet, soft and slow, he’d gently headbutt Deku in the chest deliberately as he pulls himself into a sitting position. The little smile on Deku’s face would linger with his “Morning, Kacchan.” It was a simple, short greeting, then they’d get ready and head to school at their own rates, and go about their day just like it was any other.
The nice thing about moving into the dorms is that they’re in the same building, so when Bakugo’s insomnia gets to be too much again he just has to go down two floors to crawl into bed with Deku. They’ve never talked about it, but the unspoken agreement is that these hours of sharing their sleep, they are nice to each other, they don’t sully this childhood comfort with the concerns of age and experience or disagreements. They just sleep. If they get snuggly when the lights are out, there’s nobody there to call them on it.
It doesn’t happen often, but after being in the dorms for long enough they both get careless. Deku is helping people study in the common area and falls asleep on the couch, he’s left there but covered with a blanket. Bakugo returns from his study session with Kirishima wiped out and exhausted, but stressed. He sees Deku asleep and beelines for him. He drops onto the couch next to Deku, who wakes up just enough to pick up the edge of the blanket and toss it at Kacchan. Kacchan leans towards Deku, who in turn leans towards him. They fall asleep resting on each others head or shoulder within a minute. Kirishima stopped and saw the whole thing unfold. After he realized there was no more to it, that they were both just asleep now, he began to look around for anyone else to confirm it had just happened. Uraraka was passed out in a chair, but Ojiro is seated nearby, and just shrugs.
The next day they wake up, and it’s the same as ever. Deku nudges Kacchan awake, and gets a full-body nudge back in return. Otherwise Deku folds their blanket and they both head back to their dorm rooms to get ready for the day. Neither is awake or aware enough to make note of the incredulous stares of the early risers who bore witness to their morning softness.
Bakugo Katsuki being sweet in the morning is news to anyone who has had the misfortune of trying to wake him before now. They begin to wonder why they haven’t just made Deku do it, and the unanimous choice is made that it’s Deku’s job from now on. Mineta gets the idea to give them shit for it, but is gently reminded by a few people that Bakugo will literally blow his head off if he tries it. It’s only the real and imminent threat of great violence that keeps his mouth shut.
Later in the day when Bakugo is more awake and notices the covert glances Mineta keeps making towards him, he gets a blast to the face regardless. Bakugo never lets on whether he guesses what the glances are about, or if he just figures that the gross jerk deserved it for something at some point, and nobody feels like either line of logic would be unreasonable so they don’t mention it or offer to help Mineta.
At some point when they’re alone Uraraka takes one for the team and asks Deku what the hell that was all about, and doesn’t have the heart to argue or push for more information when Deku tells her that it was nothing odd, and Kacchan was just being Kacchan, the same as he ever is. Deku isn’t lying, but isn’t not his fault if he’s the only one with full context.