For the record, I don't.

Zachary makes up songs all the time. He'll start singing & dancing to whatever comes in his mind. One of his made-up songs has stuck for quite awhile and I think it's because of my initial reaction, which included an eyebrow raising, "what?!" and some laughter.
Awhile ago, he started singing & dancing to his own hip hop version of a song he made up about me. It goes something like this:

"My momma smokes
My momma's stinky
My momma smokes
My momma's free
My momma walks
My momma sleeps..."

The first time I heard it, I didn't even realize what he had said. Again, he makes up crazy songs all the time, so I just don't always pay attention to the words.
After a few more times, I realized what he was saying. One time, on our Hilton Head trip, he was singing it loudly at a poolside restaurant. The table next to us whispered that first line and laughed quietly, probably thinking, "Oh, that poor little boy...and his mother who smokes."

It makes me laugh every time he sings it, and I've been wondering where he learned about "smoking." I'm not concerned about him knowing about "smoking," that's just a fact of life (people smoke in public...inevitably he will see that). However, I wasn't sure how he knew it was called "smoking."
I didn't want to directly ask about the "smoking" thing, so as not to make it a big deal. But I had to know. So I said, "Zachary why are you singing that song?"

Zachary: "Because I like it."

Mommy: "What does it mean?"

Zachary: shaking his skinny hips, waving his arms, "My momma smokes...My momma's stinky...My momma smokes...My momma's free"

Mommy: "Why are you saying , 'my momma smokes'?"

Zachary: shaking his skinny hips, waving his arms, "My momma smokes...My momma's stinky...My momma smokes...My momma's free"

Mommy: "Zachary, What does 'smokes' mean?"

Zachary: "Mommy, when you cook in the kitchen there's smoke."