A penis that packs quite a punch, and by punch, I mean a big dick slap to the face of your enemy (Or partner, if she/he prefers it).
To give your partner a "Willy-Whacker" is to basically get an erection that is hard enough to whack the shit out of your partner.
Just swing it to one side and knock that bitch out.
Kyle: Dude, did you just knock your girlfriend out last night?
Nathan: Yeah, I gave Gina the Willy-Whacker.
When a man ejaculates into a woman's nose and repeatedly whacks her in the back of the head forcing semen to come out of her mouth.
Yo, i gave that girl a mean Witchita Whacker last night.
A person and/or object that smacks/whacks bushes and hedges
person 1: *smacks random bush*
person 2: "bush-whacker."
person 1: "yeah I know."
When you whack your peepee on a table because you’re gay.
Dude. I’m such a homo that I got a table whacker.
Short Shorts on a man. When women wear it they call it coochie cutters. When guys wear short shorts it's called penis whackers.
Girl #1: "omg look at that guy's shorts!"
Girl#2: " OMG those are such penis whackers."