अथ बस्तिः नाभिदघ्नजले पायौ न्यस्तनालोत्कटासनः । आधाराकुञ्चनं कुर्यात्क्षालनं बस्तिकर्म तत् ॥ २.२६ ॥

atha bastiḥ nābhidaghnajale pāyau nyastanālotkaṭāsanaḥ । ādhārākuñcanaṃ kuryātkṣālanaṃ bastikarma tat ॥ 2.26 ॥

Now for Basti karma: Squatting in navel-deep water, introduce a smooth pipe as thick as a kanishtika (the diameter of your little finger) into the anus and practice Uttkatasana. In this posture the yogi contracts the base (of the pelvic cavity, the perineum) to clean the anus and this is Basti karma.