Mushroomstamp 

To slap someone with your penis in the face leaving a mushroom shaped red mark on the victims face.

That girl was so drunk when I gave her a mushroomstamp it knocked her out cold!

Mushroomstamp by M Sul May 12, 2003

mushroomstamp 

to slap somone on the forehead with the tip of a penis

"while marsha was sleeping she was mushroomstamped by joe"

mushroomstamp by Anonymous March 11, 2003

A mushroom stamp 

when a male slaps his penis off the forehead of another individual, leaving a mushroom-shaped mark.

Jen was steppin out of line, so i gave her a mushroom stamp.

A mushroom stamp by Andrew O. Ben S. TC M. October 7, 2005

mushroom stamp 

slapping a penis on top of someones forehead or on a car window

we gotta get out of here i just mushroom stamped that cops car

that guy parked so close to me i mushroom stamped his window

mushroom stamp by ass master January 18, 2003

mushroomstomp 

to slap with dick

mushroomstomp by Anonymous August 7, 2003

mushroom stamp 

when you hit someone with your penis and leave a mushroom shaped mark

That girl got mushroom stamped!

mushroom stamp by Dakota w. June 26, 2008

Mushroom Stamp 

To slap a female in the forehead with intent to leave a mark with your cock

The bitch was pissing me off, so i Mushroom Stamped her.

Mushroom Stamp by Lady Tiger January 7, 2003