When does "Paired opportunists" trigger?

Question

I have a question about the feat "Paired Opportunists":

Whenever you are adjacent to an ally who also has this feat, you receive a +4 circumstance bonus on attacks of opportunity against creatures that you both threaten. Enemies that provoke attacks of opportunity from your ally also provoke attacks of opportunity from you so long as you threaten them (even if the situation or an ability would normally deny you the attack of opportunity). This does not allow you to take more than one attack of opportunity against a creature for a given action.

So, when does it really trigger another AoO?

Case 1:

I trip an enemy with a "Greater Trip":

You receive a +2 bonus on checks made to trip a foe. This bonus stacks with the bonus granted by Improved Trip. Whenever you successfully trip an opponent, that opponent provokes attacks of opportunity.

1) I trip an enemy - I make an AoO (provoking act - trip)

2) My ally makes an AoO (triggering act - trip)

3) I make an AoO (triggering act - enemy provoked my ally's AoO from trip)

4) My ally makes an AoO (triggering act - enemy provoked my AoO from trip)

5) AoOs end (I can't make more than one AoO with "Paired Opportunists")

Case 2:

We have an "Outflank" and one of us crits:

Whenever you and an ally who also has this feat are flanking the same creature, your flanking bonus on attack rolls increases to +4. In addition, whenever you score a critical hit against the flanked creature, it provokes an attack of opportunity from your ally.

1) My ally makes an AoO (source - my crit)

2) I make an AoO (source - enemy provoked my ally's AoO)

3) An ally makes AoO (source - enemy provoked my AoO)

4) AoOs end.

So, is it right, or am I piling up a lot of excess AoOs?

And if all of this AoOs are not allowed, when does "Paired opportunist" really get you an AoO? Because all of the triggers I see already provoke AoOs from both of you.

Answer 1

Paired Opportunist:
Whenever you are adjacent to an ally who also has this feat, you receive a +4 circumstance bonus on attacks of opportunity against creatures that you both threaten. Enemies that provoke attacks of opportunity from your ally also provoke attacks of opportunity from you so long as you threaten them (even if the situation or an ability would normally deny you the attack of opportunity). This does not allow you to take more than one attack of opportunity against a creature for a given action.

To use your examples:
Greater Trip will cause the enemy to provoke an attack of opportunity from whoever is threatening that enemy - if those characters both have Paired Opportunist, they will gain a +4 untyped bonus for that attack of opportunity. This will not however provoke any further attacks of opportunity from the trip, as the action can only provoke once.

Outflank:
Whenever you and an ally who also has this feat are flanking the same creature, your flanking bonus on attack rolls increases to +4. In addition, whenever you score a critical hit against the flanked creature, it provokes an attack of opportunity from your ally.

Outflank will cause an enemy to provoke an attack of opportunity from the critically hitting character’s ally, but not the character itself. Paired Opportunist however does - in the vast, vast majority of cases - not benefit this in any way at all, as you cannot simultaneously be adjacent to an ally and flank an enemy with that same ally.

An example of where this feat does work - and works particularly well - is with Vicious Stomp.

Vicious Stomp:
Whenever an opponent falls prone adjacent to you, that opponent provokes an attack of opportunity from you. This attack must be an unarmed strike.

An adjacent ally who also has Paired Opportunist will gain the attack of opportunity Vicious Stomp affords you, and both of you will gain the +4 bonus to whatever attack roll you perform.

To put it simply, Paired Opportunist allows characters to share their sources of attacks of opportunity from primarily non-teamwork feats and class abilities (and even from some teamwork feats as seen with Outflank and how that interacts).

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Note, however, you will need to have Combat Reflexes or some other manner of taking multiple attacks of opportunity to actually leverage the extra provocations.

Answer 2

The determining factor here is identifying the "action" that triggers the attack of opportunity.

This does not allow you to take more than one attack of opportunity against a creature for a given action.

Meaning, if for instance, a creature takes the move action and cross the squares threatened by both you and your allies, you'll only get one attack of opportunity on that move action, no matter the circumstances.

You tripping an enemy provoke AoO from adjacent allies in order of initiative. Paired opportunist means that allies possessing this feat can AoO if they threaten the enemy, even if other circumstances would prevent them to do so (see later).

You crit an enemy, they triggers an AoO from you paired oppportunist partner. He acts - and you get an AoO as well.

This feat also allows you to overcome some situations where you wouldn't normally be able to AoO, such as:

• You're flat footed
• Enemy has soft cover
• Enemy has total concealment

It does not help you circumvent:

• You're not holding a weapon
• Enemy has total cover from you
• Opponent out of your Reach
• You're Paralyzed/Nauseated/Stunned

You're still limited by the number of AoO you can make in a turn.