A mistress and her slave agree upon a 'mercy' word and the dominatrix will stop when that word is uttered. But it is with subtlety, empathy and compassion and by listening to the submissive that a mistress can gauge when enough is enough. Bondage and domination ally themselves closely to the concept of arousal through feelings of power and powerlessness, punishment and being punished. The essential component is the knowledge that one person has complete control over the other - deciding what they will hear, do, taste, touch or feel. Even some eminent psychologists are beginning to understand why some people derive sexual pleasure from being bound and beaten.
Most submissive women come from very educated, middle-class backgrounds.
For some it is a way of overcoming inhibitions formed in childhood.