Exiting without using physical muscles

[Summerlander]

It's something that is really hard to convey and SOBT has done its best to put that sensation into words.  If you have indications that you are nearing the phase state, such as vibrations, imagery or sounds, and they peak, then these are good indications that the transition into the phase is being successful and you can be sure that if you move (not imagined movement but actual in terms of perception) in order to separate, then what will move is the phantom body and not the physical one.

The best thing to do is to separate and not worry about whether you will move physically or not.  The part where you move without using muscles may seem alien to you now but practitioners usually know what to do instinctively once they are conscious in that borderland state of sleep.  If you still struggle with this, do what I did when I first started.  When it came to separation, I rolled over and out - but I did it in a way that brought me confidence (after all, I was a novice and excited about OOBEs): when sounds and sometimes vibrations peaked, I would roll over and out by starting from the head.  As I moved my head to the side, I found that the rest of my body followed, and it felt unnaturally light.  Then I would sit up and walk around in the phase. 

By being subtle with the head movement at the initial stages of my practice, I found that I wasn't using muscles.  However, in instances where resistance was felt (such as cases where the physical stencil feels like a giant magnet) I was more forceful and aggressive in my efforts.  I hope this helps!