Far as i know this bug only works on Eternion and isn't much of a secret
The purpose of this bug is to enable you to increase your hp to extremly high levels
Go to wild forest, Onyxia , Battle angle or Any Mob Who casts http://www.wowhead.com/?spell=55011 which reduces your hp by 50%,
while the spell is on change your stance and your hp should increase.
I have seen ppl health get into the millions with this bug as a warrior.
Of course it's easy to get banned with this bug
I got this info from my friend but
i dont have a warrior so i couldnt test it, but i seen ppl getting banned for it