1 definition by Ol' CB
The act of masturbating under your blankets. "Opening the Umbrella" refers to the similar movements and look of someone opening an umbrella.
1. Jim: Dude, I just caught Billy opening the umbrella in his bed!
2. Earl: Oh! What are you doing there?
Steve: Nothing. Just opening an umbrella under here.
2. Earl: Oh! What are you doing there?
Steve: Nothing. Just opening an umbrella under here.
by Ol' CB August 5, 2010