Where the expression came from

It was now the Virginian's turn to bet, or leave the game, and he did not speak at once.

Therefore Trampus spoke. "Your bet, you son-of-a--."

The Virginian's pistol came out, and his hand lay on the table, holding it unaimed. And with a voice as gentle as ever, the voice that sounded almost like a caress, but drawling a little more than usual, so that there was almost a space between each word, he issued his orders to Trampas:--

"When you call me that, smile!" And he looked at Trampas across the table.

The Virginian, Owen Wister