तालुमूलगतां यत्नाज्जिह्वयाक्रम्य घण्टिकाम् ।ऊर्ध्वरन्ध्रगते प्राणे प्राणस्पन्दो निरुद्ध्यते
In plain words
Having, with effort, pressed the tongue against the ghaṇṭikā at the root of the palate; when prāṇa has passed into the upper aperture -- the vibration of prāṇa is restrained.