Spanda is the sacred tremour that exists within us. it is the essence of tantra, where true yoga begins. It satrts with the breath, the awareness of the inner vibrations. the in breath, the out breath the gap between...rest in the gap and find God.
The dance of spanda is clled the tandava. Tandava is a beautiful cosmic meditation that has four parts. Each part builds upon the other... trance dance for sure but with continual awareness of the vibration. Once you catch it it can show up anytime, upon waking up, during sex during a regular hatha yoga practice...even sitting through an unpleasant situation. I welcome anyone who is aware of this practice into this tribe.
Some references to check out
yoga spandakarika, yoga of the mahamudra, daniel odier, shiva rae, kashmir shaivism

http://tribes.tribe.net/spanda