Irresistible

I have been ploughing through Fitzgerald's translation of The Odyssey, looking for the part on the Sirens, whose song was irresistible. Odysseus or Ulysses had all his sailors stop up their ears so that they could not hear the siren song, and he had himself tied to the mast of his ship so that he could hear it but not move toward it. What could the sirens sing about which would be irresistible? Fame, fortune, eternal youth, a second chance?