In D/s, the dominant is the top and the submissive is the bottom. In S/M, the sadist is usually the top and the masochist the bottom, but these roles are frequently more complicated or jumbled (as in the case of being dominant, masochists who may arrange for their submissive to carry out S/M activities on them). As in B/D, the declaration of the top/bottom may be required, though sadomasochists may also play without any power exchange at all, with both partners equally in control of the play.