I have a 70 warlock and I love to boost people through SM. He has +1000 spell dmg when self buffed. He is a demon based and has the fel guard up but a Void should work.

I have the fel guard tag as many as possible, the more the better. Void should work for this too.
I have /petattack hot keyed and attack 3-4 or 5 items so they he's fully engaged.
then I pump out as many seeds of corruptions as I can. I'm usually get 3 off and sometimes 4.
The only flaw in this plan is if you re-seed a target before the previous seed has blown.
no curses needed, heal up pet, rinse repeat.

The reason more is better is that it's easier to make sure you hit 3 seperate targets with seed of corruption on a larger group. if it's only two or less then you need to use curses or something like that.
I have to admit I have noticed that it is much easier these days, I probably only had 600-700 spell dmg when I started doing this. Now have some gear and at +1000 spell it's really easy.
The last part of SM is AWSOME, pull about 20+ of them to the center of the room and hope you get enough seeds going to wipe the whole room, one missed seed (or a double seed) and your dead.