I use the exact same box setup (necro and shammy) for root rotting, and it's mindlessly easy and lazy...two big plusses when I don't want to have to pay too much attention. The shaman actually has 2 separate AA roots-Virulent Paralysis, which you can get down to a 30 second recast time, and Paralytic Spores. What I do is find a nice open spot with single pulls (or double if you want more pulls) and use the shaman to pull because of the instant cast cheetah AA, and malo. Basically, I just hit cheetah, run to the mob, cast AA malo, and then while he's running toward you, hit your fastest casting dot for your level. Then run back to camp, creating some distance because of cheetah speed, and park the mob with VP. Hit the macro on the shaman to start the 5-dot casting rotation. Switch to necro and hit the 5-dot macro on him. You can toss in an extra dot or two before hitting the necro macro if your dps isn't high enough to kill with just the 11 dots, but depending on what you're killing, that shouldn't be a problem. Then just switch back to the shaman and start again. You can have a solid 4+ mobs in camp cooking at all times, if you can find a spot with enough mobs to support that.
