हठयोग प्रदीपिका (योगी स्वात्माराम - ज्योत्स्ना टीका सहित सटीक)

HAṬHAYOGAPRADĪPIKĀ 23
must be made to go to every part of the body like the right toe,
etc. as indicated in Yoga practice (See Kṣurikopaniṣad, verses 6 ff.)
In the preceding verse, sāttvika-dhī means a mind in which
the Rājasa and Tāmasa elements, such as unsteadiness, indolence,
etc. have been overcome by the worship of Īśvara, earnestness and
perseverance.
7. The Yogin assuming the Padmāsana should
draw in the Prāṇa through the Moon [i.e. Iḍā or the
left nostril] and, having retained it as long as possible,
should then exhale it through the Sun [i.e. Piṅgalā or
the right nostril].
8. [Again] inhaling the Prāṇa through the
Piṅgalā, the interior should be slowly filled [with
air]. Performing Kumbhaka as prescribed, it should
then be exhaled through Iḍā.
9. Air should be inhaled by the same [nostril]
through which exhalation was made. Then having
retained the breath to the utmost [till covered with
perspiration or till the body shakes], it should be
exhaled by the other [nostril], slowly, and never fast
[as it will diminish the energy of the body].
10. If the Prāṇa is drawn in by the Iḍā, it is
ordained that it should then be exhaled by the other
[Piṅgalā]; if drawn in through the Piṅgalā, then having
retained it, it should be exhaled through the left [Iḍā].
Those who have perfected themselves in Yama, by
continually practising [breath-control] according to
these instructions through the right and left channels,
have their Nāḍī-s purified in not less than three
months.