You are skilled at pushing your foes around.
Benefit: A bull rush attempts to push an opponent straight back without doing any harm. If your combat maneuver is successful, your target is pushed back 5 feet. For every 5 by which your attack exceeds your opponent's CMD, you can push the target back an additional 5 feet.
An enemy being moved by a bull rush does not provoke an attack of opportunity because of the movement unless you possess the Greater Bull Rush feat. You cannot bull rush a creature into a square that is occupied by a solid object or obstacle.