So I forgot the title but its an isekai with a dude turned to baby and gets abilities by drinking milk from ehm ehm female breast and obviously its japanese Sorry for little info but does it ring any bell?
Something commushou Something something Edit: Commushou no Ore ga, Koushou Skill ni Zenfurishite Tenseishita Kekka
Maybe this one Commushou no Ore ga, Koushou Skill ni Zenfurishite Tenseishita Kekka Or the Hentai one byt i forgot the title.