Situation: Telling a girl when you're chatting her up that her teeth are so beautifully white and even that they could be false. Only to realise by her deep blush of embarrassment that they ARE.
Don't: Say one more word.
Do: Clutch your heart, fall to the floor and feign a Cardiac Arrest.
(Oh, but cover your balls with your hands and brace yourself for the kick that's coming
)