Stepnwolf is almost correct. The most-often quoted line in the play is : "So sage Deinem Herren, er könne mich am Arsche lecken !", which translates into "So tell your master that he can lick my ass."

More German bad words :

Hartgeldstricher (male)
  Hartgeld means coins, Stricher means a male prostitute. A male who sells his body for coins.

Arschkriecher (male)
  Ass-creeper. Someone who climbs up into other people's rectum to gain favours.