Around 700 years ago, the word ‘haunt’ first appeared in written English, at least 200 years before it took on the meaning of a ghost frequenting a place.
HZ: It just meant that way where someone haunts a bar, as in they go to it a lot, but they're not an actual ghost. But it also meant to have sex with. And I could not do enough Googling safely to find out why it had that sense, because it just came up with a lot of websites about people having sex with ghosts. So I cannot find the etymology of this middle English use of 'haunt' in the sexual sense.
PAUL BAE: You've just screwed up your Google ads logarithm by looking up succubus, haunting, "Why sex haunting?"
HZ: The things I do for this show.
PAUL BAE: Exactly.