Nectar or amrta is the food and drink of the gods. It is applied in yoga to something that flows down from the Brahmarandhra into the palate when there is strong concentration. But this is psychological, so it must be the psychic sweetness flowing into the system.

For the permanent possession of the Ananda (intimations, visits, downrushes of it one can have before); the essential condition is a change of consciousness, the coming of peace, light, etc. all that brings about the transition from the normal to the spiritualised nature. And that being so, it is better to make this change of consciousness the first object of the sadhana. On the other hand, to press for the constant Ananda immediately in a consciousness which is not yet able to retain it, still more to substitute for it lesser (vital) joys and pleasures may very well stop the flow of these spiritualised experiences which make the continuous ecstasy essentially possible.

If you want your endeavour to succeed, it must become always purer and more steady and persistent. If you practice sincerly, you will get the help needed by you.