Cutting the Cord

Reading at bedtime tonight, Kiddo on my lap, his pajama shirt pulled up to show his little boy 'pregnant belly' look. I stick my finger on his bellybutton, and kiss the top of his head.

"Mama, where's my cord?" he asks.
"Your umbilical cord?"
"Yes. Where did it go?" We've been talking a little bit about bellybuttons and umbilical cords lately. How when Kiddo was a baby in Mama's tummy, he could not breathe fresh air or eat good food, so that Mama gave him these things through the cord, in the blood that went through the cord.

"Did another baby use it?" he asks.
"No, just you. Each baby gets their own cord. When you were born, you came out of Mama's belly and then you could eat and breathe all on your own, and so you didn't need the cord anymore."

"So where did it go?" Kiddo's not giving up.

"Well, the woman who helped you to come out, she saw that you didn't need the cord and she took it away with her." I'm trying to figure out how to explain the idea that some things don't just get put into the trash when Kiddo comes up with yet another option that cracks me up:

"Mama, did she put it in a "Free" box?"