"Keep it on Wax" was a phrase used by the band Alexisonfire. It was written to express their feelings towards their former drummer, Jesse Ingelevics(2001-2005).
1 - An expression of bad blood/beef through music or poetry. The intended response is that the issue will not spill over to people who have no knowledge in the subject. Or, moreover, keep the issue silent from unrelated parties.
2 - An old gang term thought to have a similar meaning. Instead of resorting to violence the parties involved, respectively, try to resolve the issue peacefully. Presumably also through a form of music or poetry.
"Hey, you and your girl need to keep it on wax. I've got my own problems. I don't need to be dealing with yours too."