You can lower your defenses in order to improve your aggressive swordplay.
Benefit: If you are wielding a light or one-handed piercing weapon and wearing light or no armor, you can take a -1 penalty to your armor class and Combat Maneuver Defense in order to gain a +2 bonus to your parry attack rolls, disarm and trip attempts, and attack rolls for attacks of opportunity. When you have attained 5 levels of the duelist class, the penalty increases to -2 and the bonus to +4. When you have attained 9 levels of the duelist class, the penalty increases to -3 and the bonus to +6. You must choose to use this feat before making an attack roll, and its effects last until your next turn.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.