If you feel embarrassed or uncomfortable, you should express your feelings to the teacher in time. You can say, "Sorry, I can't demonstrate. I don't feel well. " Or "I feel embarrassed and can't demonstrate any movements."

If you feel uncomfortable or embarrassed, the best way is not to force yourself to demonstrate, but to respect your feelings and ask for help and support. You can ask the teacher or other students for help, or you can ask the PE teacher for help.

The most important thing is to remember that everyone has their own feelings and needs. We should respect the feelings and needs of others and try to avoid hurting them.