It starts with Mo declaring, "You have a cavity!"
Curly laughs and toddles over to his big brother.
Mo pulls out his toy drill with a flourish.
Curly opens his mouth wide.
Mo shoves the drill in his brother's mouth, turns it on, and spins the plastic drill bit - complete with spin-chilling grinding noises - for a full 45 seconds. Curly's bright blue eyes sparkle, he's loving every second.
Then they both laugh hysterically.
A few seconds later. "Hey! You have another cavity!"