Let me set the scene:
It's about 9:15 at night. We've wrestled the boys through their baths and into their beds. (And when I say "wrestle", I mean that literally. Firstborn in particular throws a mean headlock.) We've read stories and turned out the lights. I've settled in the living room, where I can keep eye on their doors and listen for the sounds of incipient chaos. To idle away the endless minutes until the boys actually fall asleep, I have turned on a video game, wherein I am cheerfully reducing zombies and other monsters to very small pieces of zombies and other monsters.
From the doorway, a small voice says, "Daddy?"
I pause the game before Secondborn has any chance of getting to a position where he can see the bloody carnage on the screen. Briefly, I consider switching the television off as well. "Secondborn," I say gently, "You need to go back to your room. You're supposed to be up on your bed."
"Yummy eats, Daddy?"
Okay, so he's not going back on his own. He hasn't just wandered out; he's a boy on a mission. And his mission, clearly, is to acquire yummy eats. So I go over to him, and pick him up - he just turned two, he's not that heavy - and I put him back on his bed. "I need you to stay up here, okay?"
"No, Secondborn. It's late, and we've already brushed your teeth."
He thinks about this. "One yummy eat?"
I'm honestly not sure whether I was more dumbfounded by the fact that he was trying to negotiate, or whether it was the fact that he'd correctly switched from plural to singular. But, well, he's clearly not going to give up on this, so: "If I get you yummy eats, we'll have to brush your teeth again, okay?"
He thinks about that. "Otay."
So I got him a bit of string cheese, and he ate it, and we brushed his teeth, and eventually he went to sleep.
The little poot has learned to negotiate.