One of the things that I've had to learn on those swivels is that, although you want to hold a good firm frame, if you clench up in order to do so, you will make your upper torso lock up and then it won't work. There's a certain resonance that has to be achieved in order for those to work. If your upper torso is too rigid, there isn't enough damping and your partner will not be able to perceive the point at which she should reverse direction. I say this with the admission that I know it in theory a lot better than I do it in practice, but when it's working the way it's supposed to, you can feel it.