Alright, This is how it's done. Lets say you are in an instance. The warrior, as everyone knows, puts sunders on the target to get aggro. Well, with a rogue, you can just piss the warrior off. Ok so, you are attacking a mob or boss and if you get enough combo points on the mob or boss before the warrior gets enough sunders on, you can use Expose Armor. This move does decrease the targets armor. So, if you have a 2-3 point Expose armor on the target, the warrior will NOT be able to use Sunder Armor, which eventually will piss him off.
Werd.