Vyasa describes this great Reality in his Visnu Purana as Sri Narayana. Sri Narayana has been shown as resting in yogika sleep in Vaikuntha. It is described that in an ocean of milk (ksirabdhi) Sri Narayana lies in yoga-nidra on a great serpent bed (Ananta), protected by the hood of the serpent. He is served by Lakshmi, His consort, who is ever at His feet.
Deep in the recesses of our personality (Vaikuntha) lies the infinite Truth (Visnu) upon the serpent Ananta (the mind) who is depicted as thousand-headed. In all regions the serpent represents the vicious mind, which at one and the same time, can think a thousand thoughts and perhaps, spill its venom through its thousand urges, inclinations, desires and passions.
In life it is found that the hooded cobra, to strike its victim, turns its hood away from his body. When the mind is turned towards the world of objects outside, it is capable of spilling its poison on to the world outside.
Here in the description, the hoods are turned upon the body of the serpent and it is lying coiled upon itself, forming a soft bed upon which reclines Lord Visnu (all-pervading). When the multi-headed human mind turns its attention inward upon itself, and the mind lies coiled upon itself, there is the state of a meditator at the moment – the infinite Visnu can be recognised as resting upon such a thoughtless mind held in animated suspension in an atmosphere of breathless devotion.
The Lord in ‘yogika sleep’ – it means that looking from the pure Consciousness, the world known to us, constituted of the perceptions, emotions and thoughts, is not there at all, just as in our sleep we do not recognise the world of plurality. But this is not the ordinary sleep (nidra); it is a moment of positive experience of the all-pervading Reality, and hence it is called the yoga-nidra.
Such a vision of the Lord can be experienced by the mind when it turns upon itself, and the mind can gain this steady introvertedness only in an atmosphere of supreme purity. Hence, it is described that He is resting in the ‘milky ocean’ in the ocean of the milk of human kindness.