School Is Boring
Many of us can recall falling asleep in class. We particularly recall a moment when we fell asleep watching a movie in class and got a D- in the subject. The important thing is not to draw the attention of your teacher. Somehow, this student managed to slip below her teacher’s radar.

The OP claimed that for an entire hour, the teacher didn’t even notice the student was fast asleep. Maybe because the teacher was sleeping internally and couldn’t care less about anyone else. Imagine if the student fell to the floor. That’d be pretty hilarious, provided someone got injured in the fall.