Being so anxious, excited, nervous or having so much euphoria that you produce so many butterflies in your tummy that they turn into poop.
David-"This song makes me SO happy, i get this fuzzy feeling inside and my tummy feels weird"

Taylor- "Do you have so much of that fuzzy feeling that you have to poo?"

David-"YES!"

Taylor-"THATS BUTTERFLY POOP
by Decast Ronaut September 28, 2010
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