phichit is an exhibitionist who takes nude selfies in public and posts them to his tumblr. One of his followers(probably Leo, unless you can think of someone who fits better) manages to track him down and catch him in the act. Semi public Sex happens. Dub con but phichit gets really turned on by the whole thing because almost getting caught is part of the thrill.

Bonus points if Phichit gets slut shamed and likes it

(Optional happy ending: they end up doing the blog together, because you can get better shots working as a team (and sex sells )