Simple means to 'toss them back faster than the boss', or bartender. It is a drinking game in which someone at a bar challenges the bartender to see who can drink a 33 ml beer faster. If the bartender loses, then the challenger receives free drinks for the rest of the night. Most prominent in certain cities in Germany, it is also popular in other areas around Europe.
I won Toss the Boss at both bars I went to last night!