Has anyone participated in internet porn, such as "bang bus" or similar sites?

Please share your stories - I'm looking for a view of the business, NOT sex stories. I think this would be a very interesting discussion on what a lot of people don't think about when they view porn.

Have you done extreme bondage/torture/bukake/gang bang porn?
How were you approached? How much were you paid? Have you continued this work?
What was your experience like? Were you treated reasonably well, or worse than you were comfortable with?