Rapid Stunning

 
Prerequisite(s): Combat Reflexes or Stunning Fist, Base Attack Bonus 6+.
 
Benefit: You may use one additional stunning attack (or other special attack that counts against your daily limit of stunning attacks) per round.
 
Special: A fighter may select Rapid Stunning as one of his fighter bonus feats. A character may select this multiple times, the effects stack.
 
Source: Complete Warrior