Balance a coaster on your head – don’t want to leave rings after all. It helps to have a flat head, but you’ve get to hold it level. Keep the beer steady with a human hand (if you don’t have a human, you can easily get one by promising them a beer). Once the head is stable, remove the human hand … NO! Put that ax down! Just remove the hand from the beer, not from the human! And voila!
WARNING: Use only “light” beer for this trick.