By maintaining a grapple hold on your opponent, you can cause it to lose consciousness.
Benefit: You must declare that you are using this feat before you make a combat maneuver check to maintain a grapple (thus a failed check to maintain the grapple ruins the attempt). If you maintain a grapple for a number of consecutive rounds equal to your opponent’s Constitution bonus (minimum 1 round), you can attempt to knock out your opponent. The victim must succeed at a Fortitude save (DC 10 + 1/2 your character level + your Str modifier) or else it falls unconscious for 1d4 rounds. Each successive round you attempt this, the target takes a cumulative –1 penalty on its saving throw. When you use this feat, you take an additional –2 penalty to your AC. Creatures that are immune to bleed damage, stunning, or critical hits are immune to this ability.