mushroom stab 

To fuck someone with the tip of your dick

I mushroom stabed jessica and she was begging for the rest of it!

mushroom stab by Wordman283 February 29, 2016

Mushroom Stabber 

Term used when a guy does a girl thats so young all he can get in is his mushroom tip(aka his dick head). You have to be really desperate or really sick or both to want this to happen.

Joe you would mushroom stab her? Thats just wrong dude theres not even any grass on the fairway.

Mushroom Stabber by The Swami February 12, 2005

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