The divine Maheswara held it in his throat, and it is said that from that time he is called Nilakantha (blue-throated). Seeing all these wondrous things, the Asuras were filled with despair, and got themselves prepared for entering into hostilities with the gods for the possession of Lakshmi and Amrita. Thereupon Narayana called his bewitching Maya (illusive power) to his aid, and assuming the form of an enticing female, coquetted with the Danavas. The Danavas and the Daityas charmed with her exquisite beauty and grace lost their reason and unanimously placed the Amrita in the hands of that fair damsel.’”

In plain words: Shiva (also called Maheswara, the great lord) kept the poison in his throat, and from then on he was called Nilakantha, "the blue-throated one." The demons got ready to fight the gods for Lakshmi and the Amrita (the drink that gives eternal life), so Vishnu (Narayana) used his magic power to become a beautiful woman, and the charmed demons handed the Amrita to her.