What's the Point of Demand in the Fort Dawgame?

Lacan: When a child asks his mother what the child asked his mother is designed to structure the presence absence relation for him. So because demand is structured by language, it can't be taken literally as Lacan's point here. "I'm like such a crum-mudgeon," he says in Beyond the Pleasure Principle. 'What am I, your babysitter?' Froyd wonders when mom drops Ernst off at home.