Covering Strike p. 91
You make a ferocious series of attacks at your enemies, forcing them on the defensive and buying your allies critical seconds needed to slip past them unharmed.
By drawing on your combat experience and knowledge of how a warrior must carry herself in battle, you make an attack that disrupts your opponents and keeps them from taking advantage of your allies' lapses.
After you initiate this boost, you can make your attacks as normal. In addition to taking normal melee damage from your blows, a foe you strike after initiating this maneuver cannot make attacks of opportunity for 3 rounds. The target still threatens its normal area; it simply cannot make attacks of opportunity.
A creature can be affected by only one covering strike per encounter. The boost only modifies your attacks for one round, but the penalty imposed by it lasts for three rounds.