look up any word, like bukkake:
 
1.
A shroom slap is when someone uses their dick to slap someone across the face, leaving an imprint looking like a shroom on their face.
Dude, guess what?! Getz told me that Jeff gave this one guy a shroom slap on the bus!
by ALF June 22, 2004
 
2.
a guy takes his dick and slaps a women across the face and leaves a shroom welt print on the womans face.
"Trav you bastard you left a shroomslap on my face!"
by travs good fuck May 23, 2009