You are skilled at pulling dirty tricks on your foes.
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.
Advanced Player’s Guide. Copyright 2010, Paizo Publishing, LLC; Author: Jason Bulmahn.