Verse 53

आमोदपुष्पवत्तैलतिलवच्च व्यवस्थिते ।वासनावशतः प्राणस्पन्दस्तेन च वासना

In plain words

stand established like fragrance in a flower and oil in sesame: from the force of vāsanā comes the pulsation of prāṇa, and from that pulsation, in turn, vāsanā.