In Merry-Go-Round in Oz, Dorothy and the Cowardly Lion (along with travel companions Prince Gules, Fess the Unicorn, Fred the Horse and Fess the Flittermouse) stumble upon "Good Children's Land," a Sugar Bowl that Tastes Like Diabetes even by Oz standards, where the population consists entirely of infuriatingly Good Children (who love doing as they're told, delight in eating all their vegetables, think "Ring Around the Rosie" is a naughty and rough game because it might get their hands dirty, and sometimes lapse into Baby Talk) and their strict Nannies. They find the children charming for about twenty seconds, after which they get increasingly frustrated and disturbed by their behavior.
When they discover that Dorothy's dress has gotten a little stained on her journey, the shocked children more or less abduct her and take her to the Nannies. When the Cowardly Lion finds her again, she's locked up in the Nursery and calls to him from a second-story window:
"Here I am," she called, "and don't be worried, because I'm perfectly all right, only I'm locked in this play room, and I can't get out!" "For heavens sakes, jump! I'll catch you!" the Cowardly Lion promised recklessly. "I can't — they've taken my dress away to wash! What's more, that Nannie is coming in a minute to give me a shampoo and a bath whether I want it or not! It's perfec'ly infuriating!"
When the heroes try to escape later on to avoid a fate filled with parsnips and mashed carrots, they are all but mobbed by Good Children and Nannies who insist that they can't possibly leave now, because it's Naptime! This is when the Cowardly Lion uncharacteristically flips out, roaring "It's not my naptime!" and frightening the infuriating Good Children and Nannies away — probably marking the only time in the series when refusing to take a nap resulted in a Crowning Moment of Awesome.
Earlier in the same book, Dorothy and the Cowardly Lion visit the Easter Bunny, who treats them to a cup of "carrot tea." The Lion hates the tea but doesn't want to say so, so he keeps discreetly pouring it out — only for the Easter Bunny to notice his cup is empty and fill it up again.
The Seinfeldian Conversations between the Cowardly Lion, the Woozy, Toto, Hank the Mule and the Sawhorse in The Lost Princess of Oz are highlights of the book. Especially funny is the one where they start discussing which one of them is the most beautiful, and the Woozy and the Lion get in some really great comments:
The Woozy sat upon his square haunches to examine Hank with care. "Beauty," he said, "must be a matter of taste. I don't say your judgment is bad, friend Hank, or that you are so vulgar as to be conceited. But if you admire big, waggy ears and a tail like a paintbrush and hoofs big enough for an elephant and a long neck and a body so skinny that one can count the ribs with one eye shut —- if that's your idea of beauty, Hank, then either you or I must be much mistaken."
But the Lion, regarding the two calmly with his great, yellow eyes, said to the dog, "My dear Toto, our friends have taught us a lesson in humility. If the Woozy and the Mule are indeed beautiful creatures as they seem to think, you and I must be decidedly ugly."