The info on the main page doesn't really help. I was testing how this attack bonus is handled by the game, cause it's really important to keep one's AC >than enemies' attack, lest they break through the Mirror Image. I noticed that the flank bonus does NOT apply if you use spells, seems only to apply for weapons. My favorite tactic at low levels is to use Sleep on enemies, then coup de grace them. Note that coup de gracing will give flanking enemies a bonus +2 to attack, but casting spells will not. So first put all enemies asleep, THEN coup de grace them. A good idea is to summon your familiar. It takes one round to summon the familiar, but the little cute animal can help you coup de grace enemies (1 per round), so you can finish them all off before sleep wears off (can be a problem at low levels due to short duration, even more so when using color spray).WRFan 19:06, August 6, 2010 (UTC)
Does it work for missle weapons?188.8.131.52 00:09, August 9, 2012 (UTC)
Proposed description and observations
Specifics: Flanking is gaining an advantageous position over an enemy by attacking where they are least able to defend. This can be achieved by attacking an enemy who is actively fighting another opponent. If successful the attacker gains a +2 bonus on attack rolls against flanked enemies and the opportunity for sneak attack.
Use: Flank attacks are more likely to be successful when attacking from behind. However, flank attacks can be achieved in the forward arc of an opponent. If also used with the Improved Flanking feat, you gain a +4 bonus on attack roll and improved odds for success.
Note: Ranged weapons can be used with this ability and although flanked target's are susceptible to Sneak Attack, they are not considered flat-footed by default.
D&D Note: This ability works quite differently than its 3.5 D&D definition and does not require attacking from directly opposite positions, only the target actively fighting another.
NWN2 Tip: Delay or time attacks until the target is actively attacking another. Because a target being hostile or in combat stance is insufficient for achieving flank attacks, as the target will react to your attack if not already busy.
Gameplay: This ability can be very effective for sneak attacks but not always practicable, as it does require tactical team work. Plus your target maybe able to avoid the sneak attack with the Improved Uncanny Dodge ability
The timing attacks is important and may require a brief delay until the target is actively attacksing another and plus its not limited to melee weapons for the attacker. https://imgur.com/saBAS0x (flanked arrows in the face of an enemy)