Definition: Okay, here's a short rhyme following your guidelines:
(Definition: (usually childish) Urine.)
My hamster, Pip, had quite a spree,
He filled his wheel with "pee-pee," you see!
A tiny fountain, pink and bright,
A miniature plumbing, pure delight!
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Would you like me to try another one?
Would you like me to try another one?