Common vs Proper vs Poopoo nouns

Simone thinks I'm in loooovvveee with nouns.  They're fine.  Sure!  But I'm just trying to teach her grammar.    She doesn't quite get it yet and we have to revisit the concept regularly.  Well she had had enough of nouns today after 45 minutes of homeschooling so when I asked her to give me a common noun she said with a smirk on her face, "Poopoo!"

I was about to scold her into taking the lesson seriously when I had a bright idea.   If I have the definition correct, I think this is a teachable moment.  I said to her, "You're right, Simone!  Poopoo is a 'thing!'  Now do you  know the name of a specific poo?"  At this point she was just giggling because I kept saying poopoo, so I answered the question for her.

"I'll tell you.  'Mr. Hankey' is the name of a particular poo! So 'Mr, Hankey' is a proper noun and 'poopoo' is a common noun!"

Hurray for knowledge!