I am a control freak, so the more control I have over a situation, the more comfortable I am.
Aside from speech class, (being graded on my performance instead of my knowledge of the subject makes me uncomfortable) I have not had a problem giving oral presentations. I like to involve the class in my presentations, such as asking questions and asking for opinions. If the class does not respond to you, just wait and the teacher will break the silence with a response.
Blushing does not necessarily go away as you get older. The best you can do is to accept it and continue with your presentation. I always blush when I talk about how my aspirin addiction for tension headaches put me in the Critical Care Unit.
One of my most uncomfortable situations occurred in Sunday School. We read a Bible passage that mentioned circumcision. Some of my classmates started discussing circumcision, including whether they had their male children circumcised (I am the only male in the class). I nearly had a panic attack: I turned red, broke out in a sweat, and started to feel disoriented.
If they noticed, they did not comment about it, and I eventually regained my composure. At the time this was happening, I also realized that this experience was far more embarrassing than when I was lying naked in the ED. I am not sure what this says about my personality