I did this in figure drawing class. I believe I brought in an old sidesaddle frame as a prop for the model to use. Incidentally this is the wrong type of sidesaddle to use to ride out hunting : it has only one horn, lacking the second horn or "leaping head" that is needed to allow a rider to stay in the saddle over jumps. And of course no one goes out riding nude. It's just a fantasy piece. I love the expression of determination on the huntress's face. Perhaps she is the goddess Dianna.