When you slap someone with your soft circumcised penis causing a small red mushroom shaped mark on the skin from the head of the penis.
by Aiden07321 June 06, 2010
To awaken one under the influence of psilocybin from incoherence with a quick slap of the hand to the face
Tony mushroom slapped Albert so as to awaken him from his incomprehensibly negative, drug-induced rant. (But Bert just became further enraged and had to be wheel chaired to bed.)
by Alphonse Drizzny January 05, 2009