We had a substitute and she didn't really care. I tried it when she was out of the class. The material didn't even cut me anyway.
I made up the excuse that I had to tie my shoe and she thought I had been on my phone. 😭
I dunno when I took this but this is off topic anyway.
I once tried to cut myself with some clay modeling tools during class. I was in a study period and felt bored. I sat in the corner so it wasn't like the teacher could see what I was doing that well.