This bug only works for a couple of seconds since its base off of the activated sweeping strike. First off, bug your sweeping strike. Then, when you see a bunch of alliance/horde or whatever, activate sweeping strikes and charge in. What will happen is, you will hit every target twice because of the bug sweeping strikes and the activated one. I do this with whirlwind and I usually end up, if not, killing everyone around me. Have fun!