The act of ejaculating while giving someone a Mushroom Tattoo, hence the Cream of Mushroom Tattoo. Also known as cream of mushroom stamp.
Man getting oral sex from Woman.

Man: hey, i'm about to cum!

*grabs Woman's head and works it faster, dick comes out of mouth. Man cums as dick comes down on Woman's forehead*

Woman: ouch! gross!! you just gave me a Cream of Mushroom Tattoo!!
by kitten_2011 April 27, 2011
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