This person put together a poll, with 3.5k responses, of lewd terms used in fiction. Results.

MerryMariLwyd get in here

"Notable omissions: Slick" add it cowards

also these are funny because you can kinda track what genre is popular based on the language, the dark romance girlies popped off on this one

member, manhood and various floral euphemisms being hated also tracks considering the amount of readers that probably got their early romance hits in the 90s-early 00s

I was a bit surprised to see 'cunt' rate so highly.

that's the dark romance influence. specifically for chapters written in the male character's pov or his dialogue

like general contemporary romance heroes are also allowed to use coarser language depending on what role they're filling, but best bet is mafia type romance

possibly also some monster fuckery, but it's the same principle of this would be a word the hero uses, not the heroine

nodnod