Snap Kick( Tome of Battle: The Book of Nine Swords, p. 32)
You have continued to hone your unarmed combat skills, and you deal more damage with your unarmed strikes.
Improved Unarmed Strike (PH) , Base attack bonus +6,
When you make a melee attack with one or more melee weapons (including a standard attack, full attack, or even a strike maneuver), you can make an additional attack at your highest attack bonus. This attack is an unarmed attack that deals damage equal to your base unarmed attack damage + 1/2 your Str bonus. You take a -2 penalty on all attack rolls you make this round.