The spirit of Tantra sádhaná lies in infusing a vibration in the kulakuńd́alinii and expanding her into Spirit. 

The significance of the term tantra is “liberation from bondage [the bondage of density, lifelessness or staticity]”.

The letter ta is the seed [sound] of dullness.

And the root verb trae suffixed by d́a becomes tra, which means “that which liberates” – so the spiritual practice which liberates the seeker from the depression or anxiety of the static force and expands the seekers spiritual Being is Tantra sádhaná.