Skip this story if you wanna see how it's done without the yada yada
As a Warlock i hate that i don't have any instant cast spells other than shadowburn wich is a talent and requires a shard
, and then there is conflagrate but ya gotta cast immolate first.
Sometimes when i am grinding mobs a horde players comes and starts to grind the same mobs, because there aren't a lot he wants all the mobs for himself, my curse of agony and corruption are instant but don't start ticking after a second or two, so i pull the mobs and the horde players starts instant casting them, for example mages can do icelances, or they simply wand, or shamans use shocks, and it saddens me that normally i wouldn't be able to kill him so i would have to leave the spawn (if it would be an alliance i would kill without thinking twice, affliction is just too strong), but warlocks can kill other faction players!
It's simple, you cast curse of agony on as much mobs as possible so you will pull them all (sorry destruction locks but this will be a tad bit harder and might result in having to take a potion and or healthstone) the other player tags your mobs by hitting them before your dots hit, with a very weak spell so you will have the aggro, change your curse of agony into curse of recklesness and repeat this on all monsters, run away as fast as you can and the monsters will aggro on the other player, their attack power will be increased and that will result in killing your faction players, if it fails the player will run away and leave the spawn, maybe call you a few names but you will have the last laugh 
Enjoy
