Teamwork Sneak Attack (Ex): Beginning at 4th level,
a nightsong infiltrator deals an extra 1d6 points of damage
when flanking an opponent or any time the target would
be denied its Dexterity bonus. Any ally of the infiltrator
who is also flanking the infiltrator’s opponent deals this
extra damage as well. This extra damage applies to ranged
attacks only if the target is within 30 feet. It increases to
2d6 points at 8th level. See the rogue class feature, page
50 of the Player’s Handbook. If a nightsong infiltrator or
her ally gets a sneak attack bonus from another source
(such as levels of rogue), the bonuses on damage stack.