This how I imagine substitute teaching working:
The sick teacher would be lying in his/her bed like they were dying. The principle would be at their bedside. The teacher would say, "Please, have (insert name of substitute here) teach my class today" and then die or go to sleep or something
A childhood belief about teachers

others believed things like this
- I used to think my elementary school gym teacher's name was "Jim Class".— Brandon Campbell
- When I was in kindergarten, I used to believe that they locked the teacher's in the teacher's lounge at night.Anon
- I used to think that teachers always had to officially announce to the whole class why someone was off sick.Anon
- I used to think that if you were the teacher's pet, you would turn into a hamster.Anon
- I used to belive that my teacher was a alien unfortunately this was true mum and said. — peter
- I used to believe that the teacher's lounge was where the teachers went to make out.— Julia