try Fuck Buddy although they're not technically besties (or idk maybe they are)
I read it it was sooo perfect in fact, that's the reson I'm looking for something similar tsym!
I'm like 80% sure there was a threesome https://www.mangago.zone/read-manga/50_x_50/
https://www.mangago.zone/read-manga/ryuuku_ai_utsu/
oh my bad lolololololl might as well join you cause I also like that bl
TSYM!! ε=ε=(ノ≧∇≦)ノ
THIS!!!!!!!!! happens during one of the first chapters, mc is a werewolf and goes into heat(???) and the ml takes him to this prostitute/escort smth like that (not a woman, but a hermaphrodite) I think but then he also joins in lmao he just uses it as an excuse.
https://www.mangago.zone/read-manga/coyote_zariya_ranmaru/
I need a bl where the 2 besties have threesomes with a girl but actually they're just using the threesome thing as an excuse they're just into each other