The Tool Tip states that Thrash always heals, and heals more with Wounds.
(Tests and Kaiserin confirmed Thrash does not heal, except when Wounds are applied.)Current description:
Deals x Slashing Damage and heals you for +x Health Points every 0.5 sec. This amount increases by x for every one of your Wounds on the target.
Correct description:
Deals x Slashing Damage. Heals you for +x Health Points every 0.5 sec for every one of your Wounds on the target.