It is sung by the townspeople of the Emerald City, who are joined at appropriate times by the group of four travelers: Dorothy (with Toto), Scarecrow, Tin Man and Cowardly Lion.
The verse of the song suggests that the people of the city do no actual work, since they "get up at twelve, and start to work at one, take an hour for lunch, and then at two they're done".
Their actions contradict that funny sentiment, however, as they are clearly doing plenty of work to "freshen up" the group of four to go see the Wizard.
The revelers' laughter is interrupted by the Wicked Witch of the West, who is circling over the city, skywriting with her broom, ordering the citizens to "SURRENDER DOROTHY OR DIE".
This article relating to "The Wonderful Wizard of Oz" or one of its derivative works is a stub.