Backcombing is basically just teasing the hair. What you do is push the hair towards the scalp. I big mistake some people make when they are backcombing is they push to much hair up at a time. When you backcomb only push about an inch at a time, and you will have nice smooth dreads, if you push to much at a time, the dreads will look really, really, really poofy and you will have loops.

I usually start in the back and work my way forward, because you don't see the back dreads very often, so if you screw up, it's not that big of a deal.

Yep, you can backcomb too much hair at a time, and what I mean by this is pushing to much hair up at a time. You should only push up an inch at a time.

You don't have to but I recommend it, you will only need one, if you use a plastic comb you will probably go through about ten. Also, you will be able to backcomb the dreads a lot tighter.

I personally think this is a painful time consuming way to make dreads. Not to mention it is not very effective with Asian hair.