Smoke rings

Three little boys were sitting around talking about their fathers. The first boy said, "My dad can blow smoke rings."
The second boy said, "My dad can blow smoke rings out of his nose."

The third boy said, "Well, my dad can blow smoke rings out of his butt."

The first and second boys where amazed. The second boy said, "Have you seen him do it?"

"No," said the third boy, "but I've seen the tobacco stains on his underwear."