A guy and a girl meet at a bar.

They get along so well that they decide to go to the girl her place.

A few drinks later, the guy takes off his shirt and then washes his hands.

He then takes off his trousers, and again washes his hands.

The girl has been watching him and opines: "You must be a dentist."

The guy, surprised, asks: "Yes .... How did you figure that out?"

"Easy..." she replies, "you keep washing your hands."

One thing leads to another and they make love.

When they finish, the girl tells him: "You must be a GOOD dentist."

The guy, now with an inflated ego, answers: "Sure, I am a good dentist. How did you figure that out?"

The girl replies:...."I did not feel a thing."