This paper explores correlations between restrictive interfaces in computational systems and restrictive interfaces in BDSM (Bondage & Discipline/Dominance & Submission/Sadism & Masochism) culture. Novel technologies often serve as pet fetish objects, but how do technologies perform as subjects in fetish culture? When digital technologies appear to us as objects, they present us with an illusion of mastery. In reality, technologies are active subjects and we, their "users," must bend to their requirements. In gaming scholarship, the process by which users must first internalize machinic logic in order to win mastery over a machine is termed learning the algorithm. Indeed, in cybernetics command and control through communication has much in common with sexual power dynamics. Both involve getting a partner to do what one wants and to not do what one doesn't want. The dominant consumerist relationship with technologies is already sexually charged. But in order to imagine an alternative, it becomes crucial to ask where power accumulates and how power functions in our interactions with devices. In a given moment of Human-Computer Interaction, who or what is a master and who or what is a slave?