Power Exchange - This term is associated with a submissive exchanging his/her authority to make decisions (whether just for a scene, or for his/her entire life), for the Dominant's agreement to take responsibility for his/her happiness and health.
On a psychological level, much BDSM play involves power and dominance, in particular power exchange, with one person willingly handing over personal autonomy. This can range from addressing another person as "Master" or "Mistress" for a ten-minute scene, to a witnessed, formal collaring with a lifelong agreement which micro-manages the submissive's life.
The latter is often referred to as TPE or Total Power Exchange.
In safe, sane and consensual BDSM, power exchange is always negotiated. Before play, the participants discuss their physical and psychological limitations, establish safewords and work out what will happen.
A submissive is a person who retains freedoms and rights, but submits or potentially submits to another in areas wider than BDSM scenes. Within a BDSM-only context, submissive is synonymous with bottom. Submissives can vary in how serious they take their position, training, and situation. Reasons for this include relief from responsibility, being the object of attention and affection, gaining a sense of security, showing off endurance or working through issues of shame.
A Dominant is a person who exercises the power to take control of a person or situation through usage of some means (such as physical, mental, financial, etc.) on a regular basis; the gender specific titles being Dom for a man, Domme or Dominatrix for a woman. Reasons for this include demonstrating skill and power, having ownership of another person, being the object of affection and devotion. This may be the fashion in which the dominant feels most comfortable expressing and/or receiving affection.
The amount of dominant or submissive traits a person may exhibit in their regular life does not determine their preferred role in BDSM play.
In most power exchange as referred to in a BDSM scene, there are limitations on the power the dominant has over the submissive, such as safewords, time limits and explicitly negotiated understandings of what is allowed.
