A former Sergeant in the Marine Corps, took on a new job as a High School teacher.
Just before the School Year started, he injured his back. He was required to wear a plaster cast around the upper part of his body. Fortunately the cast fitted 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 punks, having already heard the new teacher was a former Marine, were leery of him and he knew they would be going to test his discipline in the classroom.

Walking confidently into the rowdy classroom, the new teacher opened the window and sat down at his desk.
When a strong breeze made his tie flap, he picked up a stapler and stapled the tie to his chest.

Dead silence.........

The rest of the year went smoothly.