This is when multiple guys stretch out their sacs as far as they can over a girls head. So what it eventually looks like is a skin blanket covering her. She wont be able to see anything giving it the midnight effect.
My buddies and I got together one time midnight blanket party-"ied" this one girl and the problem is only one guy is getting his sac licked.
by Shitee Jackson October 28, 2007