1.
Comes from the word "whack"
"whackshack" Is a term used to define someone unconventional almost to an insane degree. The kind of person that will jump off a 3 storey building into a bush to impress people can be refferred to as such.
2.
Also can mean the house or hang out area for people who are whack
1.
Person- Did you see jonathon run cross that busy street last night?
Other person- Yeah, he's a total whackshack.
2.
Come on boys, let's just leave them to go back to their whackshack
When you haven't washed your hands since you last had a wank and have now found yourself shaking hands with somebody important.
Dave shook hands with his girlfriends father. He remembered how he hadn't washed his hands since having a wank and awkwardly made eye contact with him. It was a Wankshake!
When "losing it" or feeling as though one is about to "explode". Gained popularityvia the constant "whackstacking" of subpar vocalists throughout the hardcore scene.