I can do it aswell. I believe Aquanina was the one, who once wrote how do it.

What I do, is that I try to move my body. I send the signal to by body-parts, but I don't complete it, så that I actually move.

Aquanina said (if it was her), that she tries to move, and thus makes the mind think the body i paralyzed, and the mind makes the body paralyzed for real. It's hard for me to do it, and I can only do it, when I'm not breathing. It does give the same weird feeling, of floating and vibrations though.

It doesn't really induce a sleep-paralyze, unless you're already a bit into the process. That means, you've been relaxing and counting your breath (or whatever technique you use) for maybe 5 or 10 minutes.