The beer boot, or "Bierstiefeln" in German, is believed to have been introduced by a German general. The general promised his troops a drink from his boot if they were victorious in battle. When victorious, the general had a boot made from glass to fulfill his promise to his troops.
The Beer Boot Trick
Drinking from a beer boot can be a challenge and can result in an unexpected beer shower if not done correctly. The trick is to slowly point the toe to the left or right as the glass is emptied. If the toe is pointed upwards while drinking, the toe will build up pressure and release unexpectedly, spilling beer everywhere.