A primary school teacher took her class, including little David, on a trip to a working farm.

That evening David's mother asked him if he had enjoyed the trip.

"Yes it was great - we saw sheep, horses, goats, and fuckers."

His mother, shocked, asked "er, fine, fine. I know what the sheep and the rest are but what is a fucker?"

David replied "Oh, they're the animals that give us milk"

"but who said they were called, er, fuckers?"

David: "that was our teacher. Well actually she called them "effers," but we all knew what she meant."