Totally true. I was teaching in a mixed school. the kids were 16/17, nice bunch. They were fairly hyped up after lunch so we had a relaxing lead in to the lesson. I walked around the class, speaking to the children individually and noticed that they were getting more and more hysterical. Some were crying with laughter. I leaned back against my desk saying calm down, what's got in to you all?
I had my zip down, and big white silky knickers poking out the zip.
I gave out to the girls for not telling me - and it was hilarious but I did think that parents would think I was a perv!!
I (as a TA) got the job of telling a male teacher that his flies were undone - three Year 9 girls had noticed. It took me three attempts as the first two times I started laughing before I got to the front of the class & had to turn it into a walk round the class. He went SO red!
i'm not a teacher, but my driving instructor was also a diving instructor. He told me about a lesson where he was trying to help a teenage pupil's technique and he ended up shouting to her, 'X, I want you to give me more HEAD!' The lesson dissolved after that.