In plain words
The poet, to the Lord: O Araṅgaṉ [Lord of Śrīraṅgam], my Lord, who gladly took the monkeys as your own! That day, when the waves of the sea were thrown into turmoil, the trees around the mountain [Mandara] wore away and the great earth shook, as you churned with the serpent [Vāsuki] coiled tight about it: what did the mighty ones standing there [the gods and the demons] do? Tell me this distinctly, so that I may understand.