Bondage and discipline (B/D) refers to certain erotic acts that involve restraining and training submissive partners. These practices are often lumped together with dominance and submission (D/S), and sadism and masochism (S/M) to make up the acronym BDSM. Typically, a dominant partner will be the one to restrain and discipline a submissive partner. Restraints can range from simple setups, like a length of rope or handcuffs, to more intricate setups, like bondage cages or ceiling hooks. Discipline often involves correcting a submissive's behavior with physical and psychological punishments, like spanking or erotic humiliation.
Bondage and discipline is often shortened to BD, B D, or B/D.