All of us in the scene for any length of time have always known that the real power is on the bottom. Magic is the art or science of causing changes in the world through will alone. Many people try conventional magic and have little or no results. They simply don't have enough passion. But sex provides the greatest amount of passion easily available to the magician.
Sex provides energy by creating a tension that is released in orgasms.
The forces of the individuals involved flow out into the world freely at this moment. Because of the greater consciousness and separation of the individuals involved. Note carefully I am not talking about simultaneous orgasms, which are more powerful still, but the orgasms of a submissive who has been put through her or his paces. There are therefore no rules for sex magic. However there has to be good sex involved.