Srimad Bhagvata Mahapurana: Book 2: Chapter 2: Verses 10-20
His feet, which are tender like young shoots, are installed by the masters of Yoga at the centre of the full-blown lotus of their heart. He bears (a little above His left breast) a golden streak (which is held to be a symbol of Goddess Laksmi), has the famous Kaustubha gem hanging from His neck; and His chest is covered by a garland of sylvan flowers of unfading splendour. He is adorned with a girdle (round His waist ) as well as with most precious rings, anklets and bracelets etc., and looks charming with a smile that ever beams on His countenance beautified with sleek, glossy, curly and dark tresses. He is betraying His abundant grace (on the devotees) by the play of His brows, the beauty of which is enhanced by His sportful bright smiles and glances. The practicant should continue to gaze on this conceptual image of the Lord till his mind gets fixed in meditation. He should visualize with his mind one by one all the limbs of Lord Vispu (the Wielder of a mace) from His feet upwards to His smiling countenance. Even as his reason gets purer and purer his mind will become steadier and steadier, and in this way when one limb becomes clearly visible, he should leave it to visualize the next. Till one's mind gets fixed through devotion on the all-witnessing supreme Lord of the universe as portrayed above, the practicant should with a concentrated mind meditate on the grossest form of the Lord (as described in Discourse I above ) after he has finished his daily devotions. Dear Pariksit, when the striver intends to leave this body, he should not allow his mind to get attached to the time and place. Sitting in a steady and easy posture, he should control his breath and restrain his senses with his mind. Then, controlling his mind with his pure reason, he should merge his intellect (as well as his mind) in the Ksetrajna ( the conscious principle in the body), and the Ksetrajna in the absolute Self. Then, merging the Self in the Supreme Spirit and attaining final peace, the wise man should abstain from all activity. In that state (of absorption into the Supreme Spirit) Time, which is the Ruler even of gods, has no power, much less the gods or the creatures that are ruled over by them. There is neither Sattva nor Rajas nor Tamas in that state, much less the ego or Mahat (the principle of cosmic intelligence) or Pradhana (Primordial Matter). Bent upon rejecting everything other than God as 'not that', 'not that' and giving up false self-identification with the body and things associated with it the Yogis, full of exclusive devotion, embrace with their heart every moment the adorable form of Lord Visnu. The scriptures are at one in declaring this form as the supreme essence of the all-pervading Lord. The Yogi whose cravings for sense-gratification have been completely set at rest by force of wisdom acquired through the scriptures should drop his body in the following manner. First of all he should squat (on his seat) pressing the anus with his heels and then, overcoming languor, should draw the air upwards through the six places (where the six mystical circles are located). The self-disciplined Yogi should draw the air located in the circle within the navel (known by the name of Manipuraka) upwards into the Cakra located in the heart (called Anahata); thence, following the course of the Udana air, he should take it to the circle located above the breast (known by the name of Visuddhi) and, again, with the help of reason, he should gradually push it to the root of the palate (i.e.,to the top of the Visuddhi Cakra).