find a different model. There is an old expression, "when the student is ready, the teacher will appear." It fits the truth [honesty] behind creating something that is suppose to happen in a proper, non-forced manner, low stress, and completely natural by its own design, rather than subjecting someone to undue pressure, who really doesn't want to create the shot. Always remember, it is about the photo, the image, not the relationship of whether a person does or doesn't have their clothes on. I am sure DK will support me in this, if a model likes [loves] being nude in front of the camera, then everything creative will happen as it is suppose to... fun and magical.