I think she was just having a bit of a laugh, unless the teacher is a dick aside from this incident. I remember my teacher laughing at me in school. I had gone to her outside of our class to ask her for my book or something like that, and I was stumbling over words. I had my friend along with me just in case I couldn't get my words out. I stuttered for a few seconds longer than necessary and she made a face and laughed at me. It's been decades and I have not forgotten that incident. It pissed me off so bad and I started to hate her from then onwards. She can go suck a dick.