When a girl wants your penis. "Mushroom" is the head of the penis.

Usually said by a friend, can be said about your self.
Example #1-Friend

Jim- Dude, shirlena is totally on your mushroom right now.
John- Man I know, its kinda scary.

Example #2-Your self

John- Shirlena was trying to get on my mushroom last night.
Jim- Did you let her get on your mushroom?
John-Yeaaa boy!
by Evilbert October 22, 2009
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