Proprioceptive sense is your brain's awareness of the location
of all your body parts.

It is clinically described as something your brain does
automatically keeping track, like a recorder, but there is
evidence it is actually a control function rather than a
recording function, and:

when it is interrupted or damaged or stops working, or is
turned off. . . .by drugs or hypnosis, or SRA, the spirit
does release from the body (astral projection) as automatically as a baby is born when pitocin forces the
womb to contract and expel the infant.

Very risky stuff to play around with. Some do, and have.
If the spirit cannot return to the body, that is death.

In religious experience there is recorded, permitted
outings to accomplish tasks that cannot otherwise be done,
IE to assist someone in dire straights.

People who take it upon themselves to get out, and tamper
with the controls of their brain with drugs or other means,
are not on the right path, and risk serious effects.

I know of no literature that is a step by step how to, to
accomplish astral projection, that is anything but hocus
pocus.