English edit

Etymology edit

From its shape.

Noun edit

mushroom stamp (plural mushroom stamps)

  1. (slang, humorous) A mark left by slapping a person with one's penis.
    • 2001, MushroomStamper, “mushroom stamps”, in alt.fan.jessica-alba (Usenet):
      Those who wipe off the mushroom stamp are only asking for more from my gigantic mushroom stamper!
    • 2013, Jared Maxwell, Unsung: Memoirs of an Infantryman, page 112:
      Bell was walking by when he decided to interject. "How about them ole' Batman sounds? Like thwap!" We pondered what that sound could be used for.
      I made a suggestion, “Like a mushroom stamp?” Every around us laughed at that idea.
    • 2014, Regan Wolfram, After The Fires Went Out: Descent:
      It's not a good sign of your gaming prowess when you get your first mushroom stamp from a ten-year-old girl, not simply because I'm sure the act would be physiologically impossible by[sic] that aforementioned ten-year-old girl.