I think often this is likely just an attempt to "take" a word that has traditionally had negative connotations, and reclaim it as their own. The LGBTQIA community did this with "Queer." They were basically like "You know what, you flung that word as an insult and used it to cause me pain, but I'm going to take it, make it mine, and stand proudly by it."
There is power in doing this. In this case, it's showing that you're unashamed that you enjoy sex. "Yeah, sex is awesome, and I enjoy it. Deal with it."