Activities and relationships within a BDSM context are often characterized by the participants taking on complementary, but unequal roles; thus, the idea of informed consent of both the partners is essential.
The terms "submissive" and "dominant" are often used to distinguish these roles: the dominant partner ("dom") takes psychological control over the submissive ("sub").
The terms "top" and "bottom" are also used: the top is the instigator of an action while the bottom is the receiver of the action.
The two sets of terms are subtly different: for example, someone may choose to act as bottom to another person, for example, by being whipped, purely recreationally, without any implication of being psychologically dominated by them, or a submissive may be ordered to massage their dominant partner.
Participants usually derive pleasure from this, even though many of the practices—such as inflicting pain or humiliation or being restrained — would be unpleasant under other circumstances.
Explicit sexual activity, such as sexual penetration, may occur within a session, but is not essential.
Sometimes the female-specific terms "mistress", "domme" or "dominatrix" are used to describe a dominant woman, instead of the gender-neutral term "dom".
Individuals who can change between top/dominant and bottom/submissive roles—whether from relationship to relationship or within a given relationship—are known as switches.Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture is usually dependent upon self-identification and shared experience.and is interpreted as a combination of the abbreviations B/D (Bondage and Discipline), D/s (Dominance and submission), and S/M (Sadism and Masochism).Some have a policy of panties/nipple sticker for women (underwear for men) and some allow full nudity with explicit sexual interaction allowed.The fundamental principles for the exercise of BDSM require that it should be performed with the informed consent of all involved parties.There are distinct subcultures under this umbrella term.