Source: Races of the Dragon
Your draconic ancestry manifests as a muscular tail you can use in combat.
Prerequisite: Dragonblood subtype, 1st level only.
Benefit: You have a tail that you can use to make a secondary natural attack in combat. This attack deals bludgeoning damage according to your size, as shown on the table below. If you already have a tail slap attack when you take this feat, use the value from the table or your existing damage value, whichever is greater.
|Size||Tail Slap Damage|
Special: Unlike most feats, this feat must be taken at 1st level, during character creation.