The lady teacher asks the pupils what kind of medicines they know and what they are used for.
The first pupil said: Panadol
Very good! And what is it used for?
It is used for headache.
The second pupil said: Piriton.
Excellent. And what it is used for?
If you have an allergy.
Now it is Johnny's turn and he said: Viagra.
Johnny. What is it used for?
I think it can be used for diarrhea.
Who told you this?
Nobody, but in the evening my mother tells my father
'Take a Viagra, maybe that little shit will get harder.