A boy comes home one day and runs up to his mom.
"What's a bitch and a pussy?"
"Well," Mom says, "a bitch is a female dog and a pussy is a cat."
The boy thinks to himself that this doesn't sound right since the other kids were calling each other that. So he goes to Dad.
"What's a bitch and a pussy?"
Dad pulls out his Playboy and opens it to the centerfold. He draws a circle around the woman's pussy.
"Now that's a pussy, son! And everything else is the bitch!"