With effort, through a suitable tube, it should be gradually blown into the vajra cavity, to cause the movement of the air.

This verse describes an advanced preparatory technique of Vajrolī that involves the use of instruments.Śasta-nālena — through a suitable tube — refers to a catheter or thin tube traditionally made of silver, gold, or soft materials.

Phūtkāram — blowing or insufflation — indicates the introduction of air into the urethra (vajra-kandare — the vajra cavity).This practice develops control over the urethral muscles and prepares for the fluid suction technique that Vajrolī defines.

Śanaiḥ śanaiḥ — very gradually — emphasizes the need for extreme caution.These techniques pose significant risks of infection or damage if performed incorrectly.Tradition teaches them only under the direct supervision of an experienced guru, after years of preparation with safer practices.

Many modern commentators, including the Bihar School, suggest that these technical descriptions are less important than understanding the underlying principle: the control and sublimation of sexual energy.