A masochist is someone who finds pleasure in physical or emotional pain, often for sexual gratification. The "M" in BDSM represents masochism, which is a significant aspect of power dynamics in BDSM. It is also part of sadomasochism, where partners inflict and receive pain during sexual activities.

Masochists can derive pleasure from various sources of pain, either self-inflicted or administered by a dominant partner, typically a sadist. This can include activities like spanking, whipping, choking, or wearing nipple clamps. However, individual preferences may vary among masochists, and not all enjoy the same types of play. Additionally, masochists may find enjoyment in being humiliated through actions like being defecated or urinated upon, or by assuming submissive or degrading roles.