Carefully (yatnatas), (a Yogī) should perform (prakurvīta) very gradually (śanaiḥ śanaiḥ) a hissing blow (phūt-kāram) by a prescribed tube (śasta-nālena) (inserted into) the urogenital channel (vajra-kandare). (The resulting hissing sound) is due to (kāraṇāt) the movement (sañcāra) of the air (vāyu) (through the tube which has been put in the aforesaid channel)1||86||