I guess this isn't in the published stuff not only because of Wizards' dedication to make books that kids can use, but also because things like that are best decided within the gaming group, not in the published setting.
If you want your gameworld (whether it's Midnight, FR, Eberron, GH, your homebrew) to be open to such things, go ahead. If you want to have regular orgies in your world's cities that make Sodom look like a Fortress of Virtue, go right ahead. If you want to make all that happen off stage, never mentioning it in your games, it's fine.