Strictness of elder brother towards younger one like father

Bakugou is an age regressor who has trouble slipping with people around. His boyfriend Kirishima on the other hand has no idea why Bakugou tries to avoid him at night. Does Katsuki not want to be with him anymore?! ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• SOME TRIGGER WARNINGS!! (May add more) -> ⚠️NSFW ⚠️diapers ⚠️swearing (sometimes heavy) ⚠️spankings/more punishments ⚠️usage of diapers ⚠️mentions of pee or poo (relating to diapers) ⚠️mentions of mental health