Some flirting and fooling around later, the guy takes off his shirt and then washes his hands.
He then takes off his trousers and again washes his hands. Watching all this the girl says, ”You must be a dentist.”
The guy, surprised, replies, “Why yes actually. How did you figure that out?” “Easy,” she says, “you keep washing your hands.”
One thing leads to another and they make love.
After it’s over the girl says, “You must be a good dentist.”
The guy, now with an inflated ego, “Sure – I’m a good dentist. How did you figure that out?” To which she responds,
“Didn’t feel a thing.”