Bhagavatapurana 2.2.21

2.2.21

tasmādbhruvorantaram unnayeta niruddhasaptāyatano 'napekṣaḥ /
sthitvā muhūrtārdham akuṇṭhadṛṣṭir nirbhidya mūrdhan visṛjet paraṃ gataḥ //

19-21. The wise man given to contemplation should particularly arrive at this conviction (that he is no other than Brahman) and have his attachments burnt up by the strength (fire) of wisdom derived from the sastras; and then he should press his anus with his heel and lift up his breath (and bring it) into the six places (mentioned in the yoga sastra); having risen above the stage of feeling fatigue, he should carry his breath from the navel upwards into hrid (Anahatachakra), and thence into Uras that is, Visuddha-chakra, which is located a little below the neck—all following the course of the Udana? and having restrained by force of wisdom and contemplation the activities of the mind, he should slowly bring it to the root of the palate, that is to the top of Visuddha-chakra; and thence he should carry the breath upwards to the point between the two brows (Ajnachakra); having restrained the seven passages and got rid of desires (for celestial abodes and enjoyments), he should remain for a muhurta with steady vision (in perfect concentration) and then breaking open the crown of the head and intensely meditating upon the perfect Being, he should cast off the body and the organs.