When PLing another toon on my necro, the most common method I use is 'root and run'.
The necro groups with the PLee.
The PLee pulls a mob (doesn't have to do damage, pulling with a spell that will be resisted is fine, can pull with a clickie, a thrown object, whatever the PLee has).
Once the PLee has agroed the mob the necro roots the mob and DoTs it (I snare too just in case the mob breaks root - this way at least it can be kited a bit if necessary).
Once the mob is rooted and DoTed, necro runs out of range - its not that far, I can still see the PLee when I'm out of range, some experimentation will show how close you can be. You'll also need to test what dots you can use on the mob that won't kill it before you get oor. I use only snare + pyrocuror in OT for example.
The dots kill the mob and PLee gets all the xp.
We can kill pretty deep red cons this way, and when well coordinated the PLee can be tagging the next mob while the necro runs back into range for excellent efficiency. Some of the best zones I've used this in are OT, Natimbi, DS, NC - we shoot for the PLee getting 7%+ per kill.
Note that when you are killing the deep red cons there is a max on the xp per mob the PLee can get and popping the double xp AA won't increase the xp received at all.