Well, first, you can swallow or move in WILD, getting confortable makes it easier to sleep.
The electric shivers may be part of SP.
Remembering dreams is easier when you wake up without being disturbed ie, no sounds or light bothering you.
You do attain SP, the hallucinations (starry waves) are proof of that, if you can still move, then congratulations, you don't need SP for WILDing!