A submissive person in a negotiated power exchange relationship.

Collaring can be negotiated to be any length of time, or indefinite/permanent. There can be temporary or trial collars for the purpose of play. Collars of Consideration and Training might be used in the equivalence of vanilla engagement status. A permanent collar has been compared to a BDSM equivalent to a vanilla wedding ring without the state sanction. People can be collared to one or more people.

People with any identities can be collared, but they are common in Master/slave and pet handler/pet type relationships.