what is it for?
At school they are learning about medicines.
The teacher asks the pupils what kind of medicines they know and what they are used for.
The first pupil said: Aspirin?
Very good, and what is it used for?
It is used for headaches.
The second pupil said: Nytol
Excellent, and what it is used for?
To help you sleep.
Now it is Johnny's turn and he said: Viagra?
Well done, what is it used for?
I think it can be used for diarrhoea.
Who told you this?
Nobody, but every evening my mother tells my father to take a Viagra, so that maybe that little sh*t will get harder.