In plain words
The poet: Then, hearing that clamour of praise [and taking it for an uproar of demons], the beautiful, fierce serpent [Ādiśeṣa] who is the Lord's bed spat the fire of his poison. Are we [who worship him alone] not able to see the beautiful form of the one who lies on him? Surely we are. But the one born of the great flower [Brahmā] and the one with the long matted hair [Śiva] are not able even to praise him.