He informed me that where he came from (can't remember now if he was Zild or Aussie) that meant... .... to copulate.

Marty would not dare presume to speak for K1W1s, but my overwheening self-absorption means that I have no qualms about doing so. I have never heard "cut me some slack" used to mean anything other than the definition you are familiar with, nor "pull my leg", though I'm sure our West Island neighbours could create some off-colour ovine reference for K1W1-baiting, their national religion.