A grand war cry to proclaim yourself da toughest! All your attacks gain a 25% chance to increase your wounds by 57 for 10 seconds. You will be healed by the amount increased.
You may only have 1 War Bellow active at a time.
Right now, you can click off the Da' Toughest proc buff.
When it procs, it gives you a 10 sec wounds buff and heals you for the same amount.
Clicking off the buff will remove the wounds buff, the healing obviously stays as it is not a maintained buff effect. This allows it to proc more often than 10 seconds. Likely not intended. It takes a lot of micromanagement to PvP well while clicking off buffs so much, especially as a tank class, but it makes for some nice extra healing if you do it correctly.