Ritual Space
The submissive is the focusing center of the working and thus bound to  the funiture in the center of the circle, such as a horse or a St. Andrews Cross, or better yet, an open frame that would allow access from all sides.  The important thing to remember is to make the circle big enough to allow for the operator to be inside it as well.

The key to setting up a dedicated ritual play-space is to remember that you are creating a broadcasting station for the energies of your working or a receiving area for other energies.
You have to design accordingly and not just throw things together.