When a male ejaculates with enough force and velocity to hit the wall behind the bed.
Last night while I was having unprotected sex with my girlfriend, I pulled out, aimed my cannon directly at her face, and accidentally busted a wallnut. Now there's a stain above my parents' bed!
by grandma nutt May 05, 2010
the art of holding ejactulation long enough in doggie style position until the male pulls out and shoots ejaculate over his partner and above the headboard on to the wall.
"I think it's time for you to paint your bedroom, there are numerous wallnuts above your headboard".
by Mike Oxlongerest March 16, 2011
Someone who will not show their cock to anyone. They are often very sexy and have more than one girlfriend, but will not reveal or flash their cock anyway. This can make their girlfriends annoyed or sexually aggressive.
Johnny is such a wallnut. He never shows anyone his cock, not even Jessica.
by Harry Toba February 03, 2014