Mistress Kristin is back! She never did any submissive shoots anywhere, but we make her do things she has never done before. This time, we challenge her to spend some time on the One Bar Prison. This usually requires high heels: the One Bar Prison works because the model is already on her toes in high heels so she can’t lift herself any higher to escape. But for Mistress Kristin, we decided she should be bare feet, and stand on…