Well I never did it for a long time. I'm not really well spoken especially on a subject I don't understand so my chances of stuttering increases exponentially with how much I speak. If the teacher asks me about what I find hard to understand and made our conversation more deeper, my anxiety will take over me eventually and I will look like a complete idiot. Classmates definitely do not help either with their laughing, and it turns worse if the teacher is enjoying the situation. The worst of it is that I have to act it's all cool and laugh with them. I feel like a hypocrite because I sincerely want to tell each one of them to shut their mouths off, but I don't have the guts and shouldn't anyway. Over the time, I gave up on asking questions and tell myself I can search for the answers on the internet/our class group. Sometimes I succeed, but most of the time I fail miserably and do absolutely nothing about it. If I tried to find a teacher outside the class, it's either he's not there or surrounded by tens of students or/and colleagues.