The First Tooth
"What does the Tooth Fairy do with the teeth?" Ollie peered into his older brother's mouth, now less one front tooth. "She makes a throne," Harry said. "The first tooth from every kid goes into the throne, and sitting on it gives her power."
"What power?" Ollie's eyes were wide.
"Flying and invisibility. Also, she can turn other teeth into smaller fairy soldiers, but not the ones in the throne." Harry dragged a stool into the kitchen.
"Why not those teeth?"
"Because they're the ones that give her power. Duh." Harry stepped up and rummaged through a drawer.
"Oh." Ollie looked down. He might have been contemplating the statement, teeth, or marshmallows. It was anyone's guess.
"Ollie."
He looked up. "What?"
"We need to get some of that power back from the Tooth Fairy."
"How?"
"We build our own throne. We just need some first lost teeth."
Ollie's eyes lit up with thought. "Where do we get some?"
"I'd use my first lost tooth, but she already has it. But you haven't lost any teeth yet." Harry lifted the pliers. Ollie screamed. A moment later, I was there.
And that's how I stopped telling kids the Tooth Fairy was real.