S.e.x.

This old man in his eighties gets up and puts on his coat.

His wife says, "Where are you going?"

He said, "I'm going to the doctor."

And she said, "Are you sick?"

"No" he said, "I'm going to get me some of those new Viagra pills."

So his wife gets out of her rocker and puts on her coat.

He said," Where are you going?"

She said, "I'm going to the doctor, too."

He said, "Why?"

She said, "If you're going to start using that rusty old thing, I'm going to get me a tetanus shot."