Chapter Text
Izuku POV
It wasn't often that Izuku got to regress on his own terms. Not while he was in middle school and the stress of the abuse he had to suffer was eating him alive. His mother knew that he was a little, she knew it all too well but like the natural caregiver she was, she took it in stride and supported him when he slipped into his headspace.
Normally he could cope well, on bad days, where his head would go all fuzzy while in class, he was still able to get home and drop there. He never involuntarily slipped in public and wasn't eager to get that experience.
However, today was a really bad day and the gods probably hated him.
Izuku was in his second year of middle school and was currently beaten up by some of Kacchans cronies behind school. His mind was fuzzy all day and he tried to get home as fast as possible, cuddle into his mother's embrace, and forget about anything bad. But he let his guard down and his bullies found him.
After the beatdown he just laid there, he didn't have the energy to try to stay big. He just wanted his mama to baby him and protect him from everything bad. He was dropping hard and he knew that there was nothing he could do to stop himself from regressing.
With his hand in his mouth and quiet sobs leaving his tear-stricken face, he pressed himself in the corner and hoped to hide from the world.
Katsuki POV
Katsuki knew something was up with the nerd today. He was spaced out the whole day and he swore he could see him almost waddle when he walked. Like a little toddler that just learned to walk. But that wasn't news for him.
He secretly listened to the talks his old hag had with Auntie countless of times. Talks, where Inko also talked about Izuku being a little. First, he had to laugh because that was rich. Deku acting like the big helpless baby he is.
Well, he privately made fun of it until he researched the topic, as well as the reason for it. Most often it was a coping mechanism for trauma. When he read this he was sick to his stomach, all the times he bullied his former friend were spewing in his head. He never really hurt or beat him up, especially with his quirk. Katsuki wasn't that much of a douchebag. But he also never did anything to protect him and was still tormenting Izuku with his words. He didn't go to sleep that night, busy with researching and making notes on how to properly care for a little, not that he would admit it of course.
He had a lot of thinking to do.
So he knew about Izuku being a little and about his approximate age range even though he never saw him regress with his own eyes. Not that the nerd would feel safe enough around him to regress anyway.
Katsuki mellowed out a lot and forced his hag to put him in therapy. He was still an asshole but the extras knew not to lay a hand on Izuku when he was around.
Just in case Katsuki carried a pacifier with him and a little stuffie, it became a habit after the research he had done.
So imagine his surprise when he heard soft sniffing and whining behind the school. The voice was higher and more childish than usual but he would recognize that voice anywhere. He quickly rounded the corner and almost immediately spotted the nerd as he almost pathetically tried to hide himself.
Anger welled up in him as he saw how beat up he was and he had to remind himself of the breathing exercises his therapist gave him in situations like that. Seeing how Deku tried to swallow his hands whole he clicked his tongue and slowly walked to the little.
Trying to look as non-threatening as he could (Failing and looking more like an angry pomeranian) he crouched down in front of him and fished out the brightly All Might-themed paci he carried around. “Mhm hey, little guy.” he hummed calmly and tried to pry the fingers out of the other's mouth. “This is yucky.” Katsuki calmly talked to him, trying to ignore his heartbreaking as he heard the terrified sobs and the flinch.
“Come on I have a nice paci just for you.” the blonde waved the paci in front of Izukus's face and that seemed to do the trick.
Tears soon forgotten the little light up and opened his now empty mouth and let Katsuki put the adult-sized paci in his mouth. It was still a bit oversized for Izu but that seemed to just put him deeper into his headspace as he suckled, seemingly calming down. Katsuki couldn't hold his smile in as he saw baby Zuku, his heart melting.
“Ka´c… Ka-” Izus's little face scrunched up in frustration as he tried to talk around the paci. Probably too far gone in his headspace and too small to properly pronounce his name. “Sacchan” he slurred and it seemed easier for him to pronounce S sounds instead of K´s. But that was okay for Katsuki, as long as it meant that the little boy would continue beaming at him like that.
“ Yes Zuzu it's me.” he smiled softly and tried to wrangle the little koala in his arms. He was glad that he trained so much and that the younger was a lot smaller than him and lighter.
He would protect his baby at all costs.