You have learned an risky almost forbidden secret elven technique of battle.
Benefit: As a swift action, you may make a DC 25 Perform (dance) check when using Whirlwind Attack. If you succeed, you gain a +2 circumstance bonus to attack and damage rolls and a +2 dodge bonus to Armor Class until the start of your next turn. For every 5 points by which you beat the DC, the dodge bonus increases by 1.
The Secrets of the Magus