This exploit works for Delrissa (pvp boss in MgT heroic) as well as some other fights without aggro table. It works the best with Hunters or Death Knights (last one is very obvious, and not an exploit either for that one).
If you put down a Snake trap, and then Feign Death, all mobs will focus on the snakes first, giving you time to nuke them down. This fight is a pain usually, but quite easy with this.
Now, maybe this is more of a trick than an exploit, but I think it fits here better than at guides.