Top, bottom, switch

The terms top, bottom, and switch are used to describe roles during a sexual act, or they may more broadly denote a psychological, social, or sexual identity, or indicate one's usual preference. The terms top, bottom, and switch are also used in BDSM, with slightly different meanings. In BDSM, a top is the person doing something to someone else, and a bottom is the person receiving that act. In both contexts, the terms top and bottom refer to active and passive roles, not to who is physically on top in a particular sexual act. A switch is someone who can act as both a top and bottom. The older term versatile is sometimes used instead of switch.

Top
In BDSM, top can mean either a dominant partner in BDSM play (such as flogging, binding, being master, humiliating, and sexual play), or a partner who applies stimulation to another, and who may or may not be dominant.

Topping from the bottom is a related BDSM term, meaning a person simultaneously adopts the role of bottom and dom.

A service top is a person who applies sensation or control to a bottom, but does so at the bottom's explicit instructions.

Bottom
Bottom can mean either a submissive partner in sexual play (such as in being flogged, tied, humiliated, or made to serve), or a partner who receives stimulation from another, and who may or may not be submissive.

A bottom in BDSM does not have to be the submissive; for example, a female dominant may command her bottom to penetrate her.

Switch
A switch is someone who participates in BDSM activities sometimes as a top and other times as a bottom or (in the case of dominance and submission) sometimes as a dominant and other times as a submissive. This is sometimes referred to as being versatile.

Dominant and submissive
Those who take the superior position in dominance and submission scenes and relationships are called dominants, doms or dommes (feminine), while those who take the subordinate position are called submissives or subs. A top filling the dominant role is not necessarily a dominant, and vice versa, and a bottom is not necessarily submissive. Similarly, many other labels exist for both dominants and submissives, such as Master/slave or Caregiver/little.

The main difference between a dominant and a top is that the dominant exhibits control within a power exchange dynamic, while a top exhibits control within a scene. A top may or may not be a dominant.

The main difference between a submissive and a bottom is that a submissive cedes power in a power exchange dynamic. A bottom may or may not be a submissive, as power exchange does not have to be a component of their kinky play.

Many distinguish top/bottom from dominant/submissive by seeing top/bottom as an expression of physical power, while dominant/submissive is an expression of psychological power. In both types of relationships - top/bottom and dominant/submissive - consent, negotiations, and mutual respect and support for one another are keys to healthy dynamics.

Beginning in the 1970s, in some American contexts, people would identify their interests by wearing a set of keys on the side of their belt or a color-coded handkerchief in their rear pockets. This practice, called flagging, began in the gay male subculture.

Sadist and masochist
The terms sadism and masochism are the giving and receiving of physical, emotional or mental pain.