Little Johnny

A teacher is explaining biology to her 4th grade students.
"Human beings are the only animals that stutter," she says.
Little Johnny raises his hand. "I had a kitty-cat who stuttered," he volunteered.
The teacher, knowing how precious some of these stories could become, asked him to describe the incident.
"Well," he began, "I was in the back yard with my kitty and the rottweiler who lives next door got a running start and before we knew it, he jumped over the fence into our yard!"
"That must've been scary," said the teacher.
"It sure was," said the little Johnny. "My kitty went 'Fffff, Fffff, Fffff'... and before he could say "Fuck," the rottweiler ate him!"