Too Smart for My Own Good

Big Boy is officially too smart for my own good.
He throws a toy. I say, "We don't throw toys." He says, "That was a toss."
He hits the wall. "We don't hit the wall," I say. "That was drumming," he says.
He colors on the wall. "We color on paper," I say. "This is beautiful art work," he says.
He's supposed to be eating. World's slowest eater, by the way. He's taking a bite about every five minutes, talking and playing in between. "Eat," I say. "I am eating," he says, displaying the bite still in his mouth. "There's a bite in my mouth right now." Meanwhile, he is talking, singing, running around the living room, you name it. But he still has that bite in his mouth.
"If you finish your cereal, you may help me make a cake," I say. Whack. His cereal, previously perched on the table, is now on the floor, the milk splattered across the kitchen, the bowl upside down. "My cereal is gone. I can't eat it. Look, it's on the floor. Can I help you with the cake now?" he says.
Seriously? Already?
He's sitting at his picnic table, turned to face away from the table, with his feet in the plant. "Sit down at eat," I make the mistake of saying. "I AM sitting down," he says.
Help!