He was required to wear a plaster cast around the upper part of his body. Fortunately, the cast fit under his shirt and wasn't noticeable. On the first day of class, he found himself assigned to the toughest students in the school.
The smart-alecky punks, having already heard the new teacher was a former Airman, were leery of him and decided to see how tough he really was, before trying any pranks. Walking confidently into the rowdy classroom, the new teacher opened the window wide and sat down at his desk.
When a strong breeze made his tie flap, he picked up a stapler and promptly stapled the tie to his chest.
He had no trouble with discipline that year!