He gets done with it way before everyone else, and now gets to sit in silence while everyone else gets done with theirs. Having nothing else to do, he idly begins doodling on the corner of his paper to kill time, and when the time’s up, he hands his paper in with everyone else.
Later during the day, when the teacher sits grading everybody’s papers, she notices a particularly fat and ugly fly sitting on the corner of Little Johnny’s paper. Startled, she swats at it so hard, she practically destroys the entire stack of tests she has yet to grade, before realizing it’s just a very life-like, talented doodle. So, like any government employed educator, she makes Little Johnny call in his father to chastise him in front of his guardian.
When Little Johnny’s father comes in the next day, she tells him about how irresponsible his kid was, treating a test so flippantly, doodling on his paper which lead to so many other kids losing their grades, to which he replies, “That’s nothing. Last week he drew a naked chick on the fence and I’m still pulling splinters out of my dick.”