In melee combat, you can help an ally attack or defend by distracting or interfering with an opponent. If you are in a position to make a melee attack on an enemy creature that is engaging your ally in melee combat, you can attempt to aid your ally as a standard action.
You make a melee touch attack against the enemy creature. If you hit, instead of dealing any damage, your ally gains one of the following bonuses:
- a +2 Circumstance Bonus on their next attack roll against that opponent, OR
- a +2 bonus to AC against that opponent's next attack
The chosen bonus only lasts until the start of your next turn, regardless of whether your ally is able to make use of it. Multiple characters can aid the same ally, and similar bonuses stack.
Aiding another does not provoke attacks of opportunity, since it is considered a melee attack action.
See also Assist (for assisting with skill checks).