Teacher and Johnny

The lady teacher asks the pupils what kind of medicines they know and
what they are used for.

The first pupil said: Panado?

Teacher:- Very good! And what is it used for?

pupil:- It is used for headache.

The second pupil said: Piriton.

Teacher:- Excellent. And what it is used for?

Second Pupil:-To help you sleep.

Now it is Johnny's turn and he said: Viagra.

Teacher:-Johnny, What is it used for?

Johnny:- I think it can be used for diarrhea.

Teacher: Who told you this?

Johnny:- Nobody, but every evening my mother tells my father 'take a Viagra, may
be that little shit will get harder'.