Sadism and Masochism were originally medical terms that designated aberrant sexual behaviors exhibited by individuals. Sadomasochism and fetishism became visible in the late nineteenth century because certain people were being aroused by things that did not fit the standard definition of “normal” sex. But what do those terms mean today? To answer that we look at four classes of modern Sadists. And then seven uses for Masochistic pain and how to separate what is pleasurable from what is harmful, as we wrap up our look at the SM from our BDSM acronym.