"I Betcha I Can" joke

Clint was sitting in a bar having a drink and noticed that the barmaid was one hot looking babe. He slapped twenty bucks on the table and said to her, "I betcha I can keep an eye on this drink while I go to the bathroom."
Knowing the bathroom was around the corner, she accepted his bet.
He removed his glass eye, placed it beside the drink and went to the bathroom.
When he returned, he challenged, "I betcha I can bite my own nose."
She accepted his bet.
Clint took out his false teeth, nipped his nose and scooped up the money yet again.
"Okay, look," he said, "I'll give you a chance to win your money back. I betcha I can make love to you so tenderly that you won't even feel a thing."
Now this was one thing that she definitely knew about, so she accepted his bet.
Clint lifted her skirt and went to town.
"I can feel you," she said with a giggle.
"Oh, well," replied Clint, "you win some, you lose some!"