The practice of Yoga Nidra is a time honoured process of transcending the physical body. In this particular practice we expand outwards into the virbratory field where all of the permeable layers of ourselves exist, softening off the resistant and dense Self in favour of the larger Higher Self, or True Nature body,as a feild of colour, light and sound.
This is Yoga Nidra in cosmic interpretation.

May it bring you peace.