अधोगतिं अपानं वा ऊर्ध्वगं कुरुते बलात् । आकुञ्चनेन तं प्राहुर्मूलबन्धं हि योगिनः ॥ ३.६२ ॥

adhogatiṃ apānaṃ vā ūrdhvagaṃ kurute balāt । ākuñcanena taṃ prāhurmūlabandhaṃ hi yoginaḥ ॥ 3.62 ॥

The Apâna Vayu, naturally inclining downward, is thus made to reverse by force. This Mûla Bandha is spoken of by yogîs as being done by contracting and retracting the anus.