The Twin Spire Blessing buff is earned through the World PvP in Zangarmarsh. To recieve this buff your faction must control both towers. Then run back to your faction's flag talk to it's holder to have it passed to you and run it to the graveyard. Cap the flag at the graveyard to recieve Twin Spire Blessing a 5% damage buff for your faction in the zone. Originally, you could not mount with the flag, now you can, but flying is not allowed. The flag can be picked up by Druids while in Flight Form.