The technique combines nauli (abdominal isolation/navel contraction) with pressure on the feet, practiced in a “supportless” posture — possibly floating or in an inverted position.

The “retention of air” (pavana-nirodha) here is not classical breath retention (kumbhaka) but the containment of air/apāna in the pelvic region. This containment creates the vacuum that allows water to be drawn into the colon.

The description is technical and requires practical demonstration to be fully understood.