When a guy presses his cock on a mirror and says "I want to be a steak", this is a portabella mushroom
Boink...."ewww....I wanna be a steak"
by slutties_chix_on_met April 24, 2005
the foreskin of a penis flarign out wide to make the penis resemble a mushroom
that chick made me flare up like a portabella mushroom all day
by james howlett March 23, 2004