look up any word, like wcw:
 
1.
Mush-room buh-pee (said with Australian accent)

An Australian slang term used to describe the head of a penis. It originates from the viral YouTube video "Outrageous Fun".
...Stickin' it down the back of your throat, gettin' a feel of that mushroom buppy...
by OpiumFactory December 06, 2010