SakuAtsu

If you have seen my Sugawara one it’s similar. Atsumu is trans FTM and uses age regression to cope Sakusa doesn’t know about it but they are dating Kita knows and obviously Osamu does to Kita noticed a blood stain from his period and helped him but he ends up regressing you are Atsumu (btw in this Kita is the team mom bc why not)