By accident he spills flour all over himself. Then he tells his mom, "Look momma, I'm a white boy!"
His mom slaps him in the face and tells him, "Don't ever say that again! Now go tell your dad what you just said!"
So he tells his dad and his dad spanks him and says, "So now what you got to say about being white?"
And the boy says, "Well, I've only been a white boy for 5 minutes and I already hate you black people!"