This practice was recorded on a training day, and includes a demonstration of how yoga nidra as a spiritual practice might have traditionally been done. Sadhana (spiritual practice) was often performed for a variety of specific aims, and the deity in charge of making sure that merits were acrued accordingly was Shiva. The noisy drumming of the damaru at the beginning and end of a practice was both a signifier of the practice being undertaken, and a request from the aspirant for Shiva to look out for them during this time. We don't normally drum the damaru at the beginning of our nidras, so be advised that this is an unusual one in that respect: it was done for an informed and interested group who wanted to know more about the historical context of yoga nidra practice.