In some parts of the world, it means taking a group poop... However, in cooler places, it means going out as a group of 3 or 4 males and attracting several females (hopefully 2 to 3 times the number of men) and slaying them with "swords" over the course of a weekend - while only answering to the names Athos, Aramis, and Porthos. There is also a point system for what you do with the females, and the winner is the strongest muskateer for that specific period of time.
When a Woman has sex Oraly,Analy,And Vaginaly at the same time(keep in mind this requires three men). This is a bad idea because it May cause suffocation and or Vaginal,Oral or Anal bleeding.But if you enjoy killing Hookers good luck.
Steve: Hey guys gues what!
Jack&Dilon: WHAT!
Steve: I found this Crazy Chick who will let us do three Muskateers on her for only 20$
Dilon: Damn son that motherfucker is Crazy