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
by BMF Bradly Michele Farts September 15, 2016
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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.
by Kingtoocan August 29, 2009
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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!"
by Jeffonte July 4, 2017
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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
by Jim I am September 14, 2021
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When you smack a bitch with your dick and it leave the outline of your dick. The Mushroom Stamp
I met this one hoe so i gave her the mushroom stamp.
by Coochie eater 69 April 29, 2019
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