Śukadeva Gosvāmī said: O best of the Kurus, Mahārāja Parīkṣit, the demigods and demons summoned Vāsuki, king of the serpents, requesting him to come and promising to give him a share of the nectar. They coiled Vāsuki around Mandara Mountain as a churning rope, and with great pleasure they endeavored to produce nectar by churning the Ocean of Milk.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
श्रीशुक उवाच । ते नागराजमामन्त्र्य फलभागेन वासुकिम् । परिवीय गिरौ तस्मिन् नेत्रमब्धिं मुदान्विताः
śrīśuka uvāca | te nāgarājamāmantrya phalabhāgena vāsukim | parivīya girau tasmin netramabdhiṃ mudānvitāḥ
SB 8.7.1