You can hold an opponent's mouth shut.

Prerequisite(s): Combat Expertise, Combat Reflexes, Improved Grapple, Improved Unarmed Strike, base attack bonus +12 or 10th-level monk.

Benefit: As an immediate action, whenever an opponent up to one size category larger than you misses you with its bite attack, you can attempt a grapple with a –5 penalty on the check. If you succeed, you have grappled your opponent and are holding its mouth shut, preventing it from using its bite attack, breath weapon, or spells with a verbal component until it escapes your grapple. You may make this grapple attempt even if the target is out of your reach.