I have never done it in front of an entire class but I have done it for solo artists. The only odd part for me is that you are sort of supposed to know the "poses" and usually artists are too shy to tell you if they would rather you be in a different pose.
That's still impressive, Toni! Not only are you doing it for art but you also have confidence within yourself. I've always wondered myself what kind of poses are considered most acceptable for these classes lol
I think there is a bit of a science to it. Ive heard artists complain "yeah it was ok, the model didn't really know their poses though" and on the other side i have heard "yeah it was great - you could tell the model knew what they were doing". Who knew?