He then takes off his trousers and again washes his hands. The girl has been watching him and says:
"You must be a dentist."
The guy, surprised, says:
"Yes .... How did you figure that out?" "Easy.." she replies, "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, says:
"Sure - I'm a good dentist. How did you figure that out?" The girl replies:....
"I Didn't feel a thing"