 If you liked
Boku wa Mari no Naka
|
 ...then you might like
Bokura no Hentai
|
These manga share a sort of dark psychosexual introspection that is very rare. They're both filled with trauma, self discovery, complex and messy relationships, but also punctuated with quiet moments of human connection and personal triumph. I think this is a lot more meaningful of a similarity compared to the other recommendations which boil down to "they both have a bodyswapping premise."