Basically translates to "booze of the punk". It refers to alcoholic beverages that are so strong and so bad tasting that only punks will drink it. Possible examples include grain alcohol, unpleasing undiluted mixtures of various strong alcohol, and many drinks with more than 75% alcohol by volume.
The spiky haired punk pulled out a flask of grain alcohol and took a swig. He offered the flask to a friend. The friend refused saying "Blech, I don't want any of that punkerschnapps!"