A mandatory sex party is
like a normal sex party, except if you don't attend you get arrested.
People are told they will be attending a costume party, but what really happens is a wild, out-of-control
orgy involving beer, fire, and moving logs onto the road.
Allie: So, how was your costume
party last night?
Roger: It turned out to be a mandatory sex
party.
Duncan: Those actually exist???