patanjali said yOgah citta vRtti nirOdhah ie yOga is restraining the manifestations of citta (cit) – the bit of you that is conscious and self-aware etc.
tantra holds this view : The cit acquires layers as it manifests (pravRtti (प्रवृत्ति)) and loses them as it ceases to manifest ( nivRtti (निवृत्ति).
Whether the cit undergoes pravRtti out of kArmic compulsions or choice, an active effort is made to attain nivRtti and retain the pure state.
There are s’uddha (pure) tattvAs and as’uddha (impure) tattvAs, and the process of manifestation requires the acquisition of some as’uddha tattvAs.
These are lost in nivRtti.
Whenever we talk of progressing or regressing along the cakrAs, we are talking of nivRtti and pravRtti.
People who talk of sAdhaka and siddhA are referring to the tantra practicing nivRtti and attaining it.
From what I hear, the nivRtti gives you the power to do stuff like walking on water and walk through walls, but makes it hard to – say pick up a pin.
It is said that The avatArs and RSis are 6th cakra people, who nevertheless need a body to do the stuff they want to accomplish.
My guess is that you can attain nivRtti by doing stuff and exhausting your karma and becoming hurt and thus fed up, or enjoying the good stuff till you are truly fed up of it, or by destroying your karma through tantra yOgic practices. The problem with ‘doing stuff’ is that a non karmayOgi might acquire new karma to exhaust so sAdhakas don’t like that.
Everybody chooses the way that suits them individually (an then strongly recommends it to others – since human beings have a tendency to be smug and preachy.)
My leanings are to vEdAnta and not tantra, but I like to know what the fundamental principles are.
The end goal is advaita in both vEdAnta and tantra.