Then, having filled with air, pressing the chin firmly against the chest, contracting the perineum, the mind is fixed on the center.

Pūrayitvā vāyum — having filled with air — indicates pūraka, the complete inhalation preceding retention.Hṛdaye cubukaṃ dṛḍham — chin firmly against the chest — is Jālandhara Bandha, sealing the upper part.

Yonim ākuñcya — contracting the perineum — is Mūla Bandha, sealing the lower part.Thus, the prāṇa is trapped between two closures, creating internal pressure.

Mano madhye niyojayet — the mind is fixed in the center.This “center” can refer to Suṣumnā, to Anāhata chakra in the heart, or to the space between the eyebrows.Mental concentration is essential;Without it, the practice is merely physical.With dharana (concentration) applied, Mahābandha becomes a complete meditative practice.