The Lonely Mountain within the heart of the Desolation of the dragon bore within it a mound of gold with no equal. The dragon slept fast on it like a bed of jewels, when a ray of red pierced through the lids of his eyes. He was only pretending to sleep! He was watching the tunnel entrance! Then Smaug spoke.

Well, thief! I smell you and I feel your air. I hear your breath. Come along! Help yourself again, there is plenty and to spare!

It was obvious his sickly-polite offer was in jest.