When a female grabs the shaft of an erect penis, then using her other hand makes a fist and a hammer motion, smashing the head of the penis.
So jake pissed a girl off again last night, and during what he believed was his victory blowjob for winning the argument he was brought to the fetal position with a brutal mushroom hammer.
by Francis the fantastic May 20, 2014

An act of mushroom stamping, but with a giant penis, usually to a person being a complete douche. This is appropriately done by slapping said douche in the face with said penis. If correct technique is applied, the stompee will have a giant, dick-shaped imprint on his face.
by YouCanSuckABigOne March 7, 2012

The act of shoving one's penis in someone's anus, then whipping the same penis across a person's face.
by muddy69 November 23, 2009

A phallic contusion in the shape of a mushroom inflicted by a forceful blow of a penis to one's body.
by TubesteakNyourI May 16, 2003

A bruise, in the shape of a mushroom, obtained by being slapped with a large penis or penis-like object.
"Dude, I can't believe you goin' out with the new girl from accounting!"
"I'm gonna mushroom-bruise her ass, just for you. Just watch -- she won't be sittin' straight for a week."
"I'm gonna mushroom-bruise her ass, just for you. Just watch -- she won't be sittin' straight for a week."
by Dharma Midget September 7, 2016

When a girl wants your penis. "Mushroom" is the head of the penis.
Usually said by a friend, can be said about your self.
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!
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

“I lay there," she wrote, "annoyed that I was getting fucked by a guy with Yeti pubes and a mushroom dick like the character in Mario Kart." -Stormy Daniels
by real610phillyhoe September 18, 2018
