Mushroom stamp 

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

Mushroom stamp by BMF Bradly Michele Farts September 14, 2016

Mushroom Stamp 

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!"

Mushroom Stamp by Jeffonte July 4, 2017

Mushroom stamp of approval 

Generally performed by cook or some sort backline employee-type. For whatever reasons,(i.e. plate sent back, difficult diner or just don't like someone,) the cook removes his cyclops stick from his britches and strikes a portion of the meal and sends it out to be ate.

"That guy was such an ass, so I gave his mashed potatoes my mushroom stamp of approval."

Mushroom stamp of approval by Marcoleptic June 22, 2006

Mushroom Stamp FTW 

Going over to someones house, dick slapping them, leave a mark, then take a picture, and send it to the makers of C.O.D. and have the caption say "HEAD SHOT".

Oh I Mushroom Stamp FTW that hoe.

Mushroom Stamp FTW by ababyliebe August 25, 2010

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

Flying Mushroom Stamp 

The act of forcing someone to kneel down (have them stand if they are much shorter than you), then removing all your clothes, and getting to a good distance. Once you have achieved the desired distance, you then run and jump, swinging your hips causing the head of your penis to slap them in the face, leaving a bright red imprint shaped like a mushroom.

Please exercise extreme caution when performing the Flying Mushroom Stamp. Serious injury may (and often will) occur.

I performed the Flying Mushroom Stamp on that bitch, dawg!

Flying Mushroom Stamp by Kaj Darkwind May 16, 2010

purple mushroom stamp

NOTE: this move requires a flacid penis. while dangling your dong in front of a woman in an attempt to 'woo' her, you grab the base of your member and swing it in a counterclockwise ninja motion smacking her flush on either cheeck leaving a welt resembling a purple mushroom. in germany this is seen as a sign of affection...in tennessee it will get you killed.

i wanted sandi to know that i was into her...so i gave her a purple mushroom stamp. in return she hooked me up with an award winning clark bar

purple mushroom stamp by DJ KNUCKLES March 8, 2005