The doctor told him to take a specimen cup home, fill it, and bring it back the next day. The elderly man came back the next day and the specimen cup was empty and the lid was on it.
Doctor: What was the problem?
Elderly man: Well, you I tried with my right hand...nothing. So, I tried with my left hand...nothing. My wife tried with her right hand...nothing. Her left hand...nothing. Her mouth...nothing. Then my wife's friend tried. Right hand, left hand, mouth....still nothing.
Doctor: Wait a minute. You mean your wife's friend too?!
Elderly man: Yeah, and we still couldn't get the lid off of the specimen cup.