I usually get really close to lucid dreaming on friday and saturday nights. It's usually unintentional, and my body starts to tremor, and I start seeing colors and feel like I'm being sucked through a portal or something. But I end up clenching my teeth, or at least think I do. I worry that I'm going to bite my tongue or lip and soon snap out of it, and completely forget that night's dream. Can I lose the ability to control my body, but still control my jaw/face? Or once I get to that phase, am I just imagining the clenching?

Also, how close would the 'portal' thing be to me actually dreaming? Is there more after that or do I have it down?