Any survival bl with smut, like they're in the wild or something.
https://www.mangago.me/read-manga/zombie_hide_sex/
its not the one I was looking for, cause there's one with a red hair dude and the uke looks similar to yoon bum from killing stalking
https://www.mangago.me/read-manga/omerta_kochou_no_yume_no_kate/ suddenly got reminded of this but tw// r*pe
Also Itou-san kind of fits your description so feel free to check it out if u haven't ヾ(❀╹◡╹)ノ~
https://mangafire.to/read/shall-we-bathe-your-grace.902zm/en/chapter-53
thank you for your help TT