I don't have it analyzed as well as that, but I know like I know my name that the sensations come while I'm asleep and wake me up.In 1, I am still aware enough to feel the sensations and know I am moving. I try to stay asleep, knowing that it will not work. In REM, I can tell because just as the need to urinate or vomit becomes part of your dream, my movements do. The movements are in my dreams, as is my prone mattress dance. This eventually takes me to stage 1, where I realize I am not going to overpower it and I have to wake up completely.
Oddly enough, I don't dream WED; I was surprised to read of it
A weird thing that's been happening the last year or more is that I wake up to realize I've been sleeping sitting up. Sometimes I drift between a Stage 1 type of awareness (sleeping but aware that I'm sleeping) and something deeper. Often, in the asleep-but-aware state, I sort of know I'm sitting up, but it confuses and frustrates me - I know something is off, and I feel a mental restlessness, like I want to do something about it but can't muster the brain tissue to think it out. I think that happens when I've been sitting up for a while. Other times I don't think I'm sitting up long before I wake up. Sometimes I wake up as I'm falling over (always in time to catch myself, so far).