I have.
It happened just before Christmas, and I was hoping to get some more cash for presents that year. I had given my contact information to the local community colleges head of arts department. And I had to wait very long until they phoned me back. I was a bit nervous when I arrived at the school, but it soon vanished as I saw the room and the people, some were familiar faces from other art group I attended, the teacher was nice enough and explained how the following two and a half hours were going to be. It started with a number of quick poses, for the students to practice fast sketching - 5 minute pose, 3 minute pose, 2 minute pose, 1 minute pose. And after that it was a series of longer poses, 20 minutes at a time and moving on the next pose, or doing the same pose for a longer time. With pauses in between of course.
In the end it was quite simple job. You follow the advice of the teacher about the next pose - if she had one particular in mind. Otherwise it was very much up to me what kind of pose I would strike. I had a very good experience.
And there aren't really any prerequisites, all kinds of models are needed - but it takes some effort to keep a pose.