You're a paragon of down-and-dirty fighting.

Prerequisite(s): Improved Dirty Trick.

Benefit: You gain a bonus equal to half your tier on checks to attempt a dirty trick, and to your CMD when an opponent attempts to perform a dirty trick on you.

These bonuses stack with those granted by Improved Dirty Trick.

Furthermore, you can make an attack of opportunity against any creature that attempts a dirty trick maneuver against you, unless it also has this feat.