Srimad Bhagavatam Canto 08, Chapter 07, Text 01

SB 8.7.1

sri-suka uvaca
te naga-rajam amantrya
 phala-bhagena vasukim
pariviya girau tasmin
 netram abdhim mudanvitah
arebhire sura yatta
 amrtarthe kurudvaha
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Sukadeva Gosvami said: O best of the Kurus, Maharaja Pariksit, the demigods and demons summoned Vasuki, king of the serpents, requesting him to come and promising to give him a share of the nectar. They coiled Vasuki around Mandara Mountain as a churning rope, and with great pleasure they endeavored to produce nectar by churning the Ocean of Milk.
Srimad Bhagavatam Canto 08, Chapter 07, Text 02