I get this too!! It's exactly how you explain it. I get the weird sensation like a brain zap, or a humming, or a feeling that I'm falling when I'm kind of tired. If I lay down and stay still, I can project my dream self from my real body and walk around my subconscious like I'm in a lucid dream. However, I'm completely awake and I can usually move my real body whenever I want. It feels like a skill to develop. Sometimes (usually at night), the feeling puts me into sleep paralysis. I either try to turn it into a lucid awake dream thingy or I fail and scare the shit outta myself. Sometimes I'll get the body zap, humming, or falling/spinning feeling all day whenever i turn my head or blink hard. Its like I just have to go into the awake dream thing. It's been happening for almost 3 years so it's weird seeing someone else describe the same thing.