At school little Johnny learns about medicines.
The lady teacher asks the pupils what kind of medicines they know
and what they are used for.

The first pupil said, "Tylenol."
"Very good said the teacher. and what is it used for?"
"It is used for headache."

The second pupil said, "Nytol."
"Excellent. And what it is used for?"
"To help you sleep."

Now it is Johnny’s turn and he says, "Viagra."
"Johnny, what is it used for?"
"I think it can be used for diarrhea."

"Who told you this the teacher asks?"
"Nobody, but every evening my mother tells my father take a Viagra, maybe that little shit will get harder."

The teacher faints!