i stumbled upon an article that Thumper wrote in his blog Denying Thumper about explaining D/s and the different layers of the nuances of the D/s relationship. Not only was his article informative, but the other blog post he referred to is even better.
Both Thumper and the other writer not only clarify how D/s fits into a day-to-day life, but also is informative to the non-D/s community. You could send somebody who does not understand the dynamics of this type of lifestyle and i would feel that they would come away with a better understanding. Please go and read both articles since i do not even to attempt to try to do justice to the subject matter.