Today I tried to WILD for about an hour and I had HI and numbness of my body. Nothing new, except one thing: when I tried to wake up and get up I realised that exactly two of my left hand’s fingers were numb and paralysed, though I could move them a bit.
Was that some kind of SP or was my hand’s circulation interrupted? That hand was lying on my chest and the other one on my leg.
Dunno, but the same thing happens to me alot. 
Is it a sign of sleep-onset REM sleep? Can it help in determining whether you can do WILD without WBTB at that moment? I did this without WBTB.
Sounds like the onset of REM to me particulary since the hands are the first part of my body to become paralysed when I WILD.
You would know if it was just an issue of cutoff circulation or REM starting, they are two very different feelings from my experience.
As for the WILD without WBTB it is possible but unusual. Normally your body will go from stage 1 to stage 2 to stage 3 to stage 4 sleep and then to REM after that.
It is generally accpeted that you cannot retain conciousness when you enter stage 4 sleep so if REM was beginning you were skipping stage 1-4 sleep and going straight to REM which is characteristic of what happens when a person takes a nap.
Why are stages 1-4 skipped? What is the difference between a nap and normal sleep to our bodies? How does the brain decide to skip 1-4 or not?
This typically happens when someone is sleep deprived or the total opposite. The reason for this is that REM sleep is far more important than the stages 1-4. If you prevent someone from REM for a night they will feel like they haven’t slept.
If you keep someone from stages 1-4 sleep they will still feel quite well rested.
When we nap we have typically already has some sleep and it is at a diferent time than usual so the body tends to enter into REM sleep first and focus primarily on getting REM sleep. That’s why WBTB is effective, because we wake up and then normally go right into REM making for super-easy LD.
It depends on situation, if you are very sleep deprived the brain needs REM sleep badly and will enter it almost immediatly, why it goes directly into REM sleep after you have had alot of sleep, I’m not sure.
BTW, other factors such as drugs or alchol can affect sleep patterns.
Thanks a lot, Lucidity_Master!