BDSM

BD is a compound acronym derived from the terms bondage and discipline next letters follow by the D.
DS (Dominance and Submission) next letter is S
SM (sadism and masochism)

BDSM encompasses many activities, including — but are not limited to — forms of dominance, submission, discipline, punishment, bondage, sexual roleplaying, sexual fetishism.

Activities and relationships within a BDSM context are characterized by the fact that the participants usually take on complementary, but unequal, roles. Typically, participants who are active — applying the activity or exercising control over others — are known as tops or Dominants. Those participants who are recipients of the activities, or who are controlled by their partners, are typically known as bottoms or submissives. Individuals who move between top/dominant roles and bottom/submissive roles—either periodically within a relationship, or from relationship to relationship—are known as S/switches which means either top or bottom.

The term "Bondage" describes the practice of restraining for pleasure. Bondage is usually, but not always, a sexual practice
Punishment can be pain caused physically (such as caning), humiliation caused psychologically (such as a public flagellation) or loss of freedom caused physically (e.g. chaining the Bottom to the foot of a bed)

Dominance and submission
is a set of behaviors, customs and rituals relating to the giving and accepting of dominance of one individual over another in an erotic or lifestyle context.

Sadomasochism refers to the physical aspects of BDSM. Sadism describes sexual pleasure derived by inflicting pain, degradation, or humiliation on another person. On the other hand, the masochist enjoys being bound, spanked or suffering within the consensual scenario