noun: Oxycontin or black tar heroin, when free-based off of aluminum foil. Refers to the sizzling sound the drug makes as it is heated on foil.
verb: The act of free-basing Oxycontin or black tar heroin. Often "sizz out".
"Hey man, have you seen my sizz lying around anywhere? I can't find it and I want to do some before I go the the DMV."
"You trying to sizz out right now? I've got a little left, you can rip it if you hit me back tomorrow."