Improved Dirty Trick

Combat

You are skilled at pulling dirty tricks on your foes.

Prerequisite: Int 13, Combat Expertise.

Benefit: You do not provoke an attack of opportunity when performing a dirty trick combat maneuver. In addition, you receive a +2 bonus on checks made to attempt a dirty trick. You also receive a +2 bonus to your Combat Maneuver Defense when an opponent tries a dirty trick on you.

Normal: You provoke an attack of opportunity when performing a dirty trick combat maneuver.

Source: Advanced Player's Guide