Bob Monroe describes this as log rolling. It is useful for some to separate the first energy body, what Bob called Locale One. This is the body with which one explores the current physical planet, the one which can look back and see your physical body on the bed but in to which one's consciousness is focused. It is a copy of one's physical body made from finer susbstance (higher frequency?).

The second energy body, what Bob Monroe called Locale Two, is the one with which one can explore the non-physical Universe (and beyond). It is completely non-physical for me but has some physical attributes when needed...

Other techniques are climbing a rope, imagining a ship rolling up and down on the waves, climbing steps, and on and on. The book MASTERING ASTRAL PROJECTION by Bruce Mercer and Robert Bruce lists many more than these to leave the body.

Thomas