The best way to have thin dreads is to make the sections thin when you start them. There really isn't a good way to thin them once you have already put them in. You can tie string around the roots and make them grow in thinner sections, but if cut them or pull them apart it really tears up the dread.

If you cover them with a nylon when you sleep it will make them lay down.

It's not really a good idea, because the dread will start to unravel because the hair that was holding the knots together before is gone. You will have to wait for the tip to lock up again and it's just a pain. But if you are going to do it the best way to cut it is like a flower, cut it at an angle.

I tried it once, and I didn't like the way my hair looked afterward, it looked really unhealthy and singed, a lot of the hair broke off, and it smelled so bad. The tips didn't have the blunt look I was looking for either they just looked fried. If you are going to do it make sure you don't have any wax or products in your hair, most hair products are very flammable. But I got the best results just rolling the tips in my palms.

You should pull them apart and then put a rubber band around the loose hairs, wax them and palm roll. And keep an eye on them, because if it happened once it can happen again.