Little Johnny drew a fly on the class grade book.

The teacher noticed the fly sitting on the grade book,
so she smacked it with a ruler. But, the fly didn't fly
away, so she smacked the grade book once again.
Again, the fly didn't fly away.

This drove the teacher mad, so she started to pound
the grade book with the ruler and, as a result, the grade
book quickly amounted to nothing more than a bunch
of torn sheets of paper.

With the class laughing, the embarrassed teacher
realised what had happened.

That afternoon, the teacher called Little Johnny's father
to school. "You see what your son did to our class grade book?" she said.

"That's nothing," remarked Little Johnny's father. "Last
week, he drew a naked woman on the fence in our yard
and I've been pulling splinters out of my dick ever since!"