What you do is make a line that rhymes with the previous sentence (And eventually it will make either a song or poem)
After 3 lines, a fresh new sentence can take place so it won`t always rhyme with the first sentence (Do not put words that are unable to rhyme, aka Angel, or Purple)
Example:
1:There once was a man named Paul
2:He was stuck in Taco Bell's bathroom stall

I shall start
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I once popped popcorn without the lid