Sleeping Method - Vibration in body

Recently while trying to sleep I used this method of getting to sleep posted here in the forums many months ago.
It was to count down from 100 to 0 with each inhale and exhale as one count.

Anyway when I got to around 30 my entire body started vibrating. To say the least it was rather perplexing. Does anyone have any insight into this experience? Like why and how?

Thanks.:)

Oh and I'm posting this here because even though I joined last year I haven't posted at all really and still consider myself very much a noob.

This could be what's known as sleep paralysis. Some people experience vibrations, while some feel like they're floating on water, or falling. You can also have hypnogogic imagery, so you see swirling colors in your eyes, stars or many other objects. Even sounds, smells and taste can take place.

Because your body is lying still, you may feel some itchiness or a feeling that you're not comfortable. This is because your body is trying to check if your mind is still awake. If you ignore it for long enough, it thinks that the mind is asleep and your body 'shuts down', however, your mind is still awake.

-- Dairyman

Ah yes. I don't remember swirling colours and such I just remember rather vigorous vibrations.
Interesting nonetheless.

And yes I get that itching or sudden urge to move a part of my body. I wish I didn't.