And the Ocean replied, ‘Be it so, as I shall not go without a share of it. I am able to bear the prodigious agitation of my water set up by the mountain.’ The gods then went to the king of tortoises and said to him, ‘O Tortoise-king, thou wilt have to hold the mountain on thy back!’ The Tortoise-king agreed, and Indra contrived to place the mountain on the former’s back.

In plain words: The Ocean agreed, as long as it got a share of the nectar, and said it could handle the stirring. The gods then asked the king of tortoises to hold the mountain on his back. He agreed, and Indra, king of the gods, set the mountain on him.