Looking at the new story I just submitted, it seems that I’m following Chekhov’s Law for gay porn writers: When you introduce a son in the first act, he must go off in the third act.
(Seriously, though, Chekhov’s Law is a good thing for all erotic fiction writers to keep in mind. Foreshadowing helps to create suspense, and when you drop in little hints of where the story is heading, readers become more attentive).