How do Antonio and Sebastian mock Gonzalo's Utopia?

In Act II, Scene I, King Alonso has landed on the island, with his brothers Sebastian and Antonio, noblemen Adrian and Francisco, and the councilor Gonzalo. Gonzalo tries to console Alonso upon their good fortune of surviving the shipwreck‹but Alonso is grieved‹not only because his son Ferdinand is missing and presumed dead, but because he was returning from his daughter's wedding in Africa, and fears he will never see her again because of the distance. Antonio and Sebastian show great skill with mocking wordplay, and use this skill to stifle Gonzalo and Adrian's attempts to speak frankly to the rest of the party. Ariel's magic makes the party fall asleep, with the exception of Antonio and Sebastian.