A Weave Whack is when someone has in synthetic braids/weave and turns expectantly and whacks/whips you in the face with said weave/braids.
Me: Yeah and so thats when Keisha-
Person: HEY SHAUNA
Shauna: *Turns real fast and whacks in face with weave*
Me: Damn Shauna you just weave whacked me
Shauna: Haha my bad!
Clam whack is when you slap a female in the pussy so hard they make blue whale mating calls
Bro1: dude I thought you were going to Stacey's house tonight? what happened?
Bro2: nah man she got mad at me after I clam whacked her as a joke.
Bro1: Lmao you aint getting no coochie tonight