when you or someone close to you has abnormally low hanging balls and you proceed to dribble them against a hard surface and slam dunk them in their navel
you boys ready for the big slam junk competition tonight!?
by Ice Kingz January 04, 2011
1 more definition
A variation on a handjob, a slam junk is performed by jumping in the air with your arm outstretched, then slamming your hand, masturbation-style, onto the recipient's dick as if dunking a basketball. The more preferable variety of this position is performed with the recipient at a slightly higher elevation of 10 feet, although this is optional.
Yo, man, go lay down up there and I'll give you a slam junk!
by ACID13X February 29, 2012