Dad takes son to school for his first day.

A man is driving his five-year-old son to school for his first day.
Suddenly the boy shouts out "Daddy! Daddy! Look at those moo cows in that field."
His father says "Hang on, you're a big boy now, you must use adult names. It's a cow, not a moo cow."
The boy is quiet for a while then suddenly shouts out "Daddy! Daddy! Look at those baa lambs in that field."
"I've told you" the father replies. "You're a big boy now, you must use the adult names. It's a lamb not a baa-lamb."
He drops the boy off at school and returns later to take him home.
"How did your first day go, son?" he asked.
"What did you do?"
"We did some sums and we all read a story" he replied.
"Oh" said his father.
"What was the story called?"
"Winnie the Shit!"