see also mushroom bruise and mushroom tatoo. It is the mark on a woman(or man), after being whipped by an erect penis.
did you see the mark on her face?, that must've been a blue mushroom
by mos def and talib kweli are blackstar March 12, 2005
The act of gripping an erect penis by the shaft right below the head and punching the penis until it is completely bruised.
I was with this guy last night and he totally wanted me to blue mushroom him!
by johnredcorn69! August 24, 2009