Mushroom Stamp

Mushroom stamp is a slang term referring to the act of slapping the head of a penis (which may be described as mushroom-shaped) against another person’s skin—commonly the forehead, cheek, or another body part—leaving a mark or “stamp.”

In kink or play contexts, this may appear as part of humiliation, marking, or CFNM (clothed female, naked male) scenes, where the gesture can serve as a symbolic “marking” or playful act of dominance.

It is important to note, however, that leaving an actual mark with the penis likely isn't possible without very significant force. Because this force is likely to be at least as painful for the penis owner as the recipient of the "stamp," many believe this slang term may be more urban legend than reality.