In a pocket of his knapsack he'd found a last half packet of cocoa and he fixed it for the boy and then poured his own cup with hot water and sat blowing at the rim.
You promised not to do that, the boy said.
What?
You know what, Papa.
He poured the hot water back into the pan and took the boy's cup and poured some of the cocoa into his own and then handed it back.
I have to watch you all the time, the boy said.

Cormac McCarthy