General: orgy
Orgy
A gathering of five or more individuals to have sex freely among each other in various combinations (frequently of more than two each). Doesn't necessarily include everything with the group sex tag, because if it's merely a pair (or more) of couples it's not actually an orgy, just a bunch of couples having sex in the same location. An orgy is also distinct from a gangbang, which consists of a group of at least three people all having sex with one individual (at once or sequentially).