Darth Vader's brains
the act of a male grabbing his ball sack near the base squeezing out his testicles until the the ball sack skin is smooth in a similar shape to Darth Vader's helmet. Originally performed in a barracks in Quantico, VA 1996.
The first time I showed Darth Vader's brains to my girlfriend she thought It was gross, but now she loves it and asks me to do it all the time.