The act of trapping a person underneath a blanket and physically assaulting them. The blanket is used as: 1) a deterrent for the assaulted person to fight back; and 2) a way of keeping the assailants anonymous.
We're going to give that annoying bastard a blanket party tonight.
A violent group attack on an unpopular GI. Usually done in the middle of the night, in a barracks situation, the victim’s head and body is covered with a blanket (preventing him/her from fighting back or identifying assaillants). Occassionally these attacks are used to bring a barracks bully into line but unfortunately hundreds of attacks per year are aimed at suspected gays. This type of hazing is tolerated by noncommissioned officiers who see it as a means of "self policing" among privates and trainees.
Smith over there has been a real fuck-up and kept us from getting a pass into town last night. Let's throw him a blanket party tonight.
Usually a reaction to a long-term annoyance brought about by one person, a blanket party is where an unsuspecting person (individuals only, not on groups) is taken by surprise when a blanket is thrown over them and they are wrestled to the ground, then beaten with blunt objects by other members of the group.
After the first blanket party, they usually get the message.