I have no interest in pain, however frustration is definitely on the menu. I try to set my sessions up to get myself as close to the edge of orgasm as possible and maintain that edge for as long as possible. Sometimes I drift into a reverie, my private self-imposed bottom space. There doesn't seem to be a magic way to achieve that. It just happens sometimes. Those times are the best, however I've never had a "bad trip" of any kind. A day with bondage beats a day without.
Good question.
Max