A person who has been given or is assumed to have been given a multitude of mushroom stamps. Could be used as an insult or a term of endearment.
So you think you're better than me little miss mushroom stamp.
Hey little miss mushroom stamp you missed drinks last night
When you hold back your cock and let it go to hit someone in the forehead,thus leaving a mushroom stamp
Back off before I hit you with this mushroom stamp
Sorry about the mushroom stamp, hope your dad doesn't see it
the mark left on ones body when smacked with the head of a penis.
I smacked my dick on her forehead and left a mushroom stamp on her.
Dipping the head of your penis into ink, and using the head as a stamp.
"Hey bro, did you see how wasted Steve was last night?"
"Yea! I gave him a mushroom stamp on his cheek!"
When throwing a fried mushroom at someones head and it explodes. The hot grease leaves the impression of a mushroom on there face
Wow did you see Seth Pittsburgh mushroom stamp Jason last night at the bar