It would appear that the subject matter being taught in this classroom is a little bizarre. I don’t remember being taught the proper mechanics behind stretching and yawning … however, I will say that I love both stretching AND yawning. Saying that just made me yawn.
Did you yawn after looking at this photo? I just did again.
By the way, this is a photograph taken by Frances Benjamin Johnston, available at the Library of Congress.
When I was little (through 2nd grade) we were required to put our heads on our desks and nap. It was torture for us since we didn’t fall asleep but were required to keep heads down and make no noise. This yawn and stretch may be a prelude to the nap time.