This fetish is primarily found within BDSM culture although not exclusively found in it. In BDSM relationships, the collar symbolizes submission or ownership. The partner wearing the collar belongs to the Dominant and is under their power. In many cases, the collar is essentially interchangeable with a wedding ring. There is often a collaring ceremony between the Dominant and submissive during which the collar is placed on the submissive and certain promises are made.
Because of the way D/s relationships are often viewed by society, submissives often have removable collars or "day collars." Day collars are generally necklaces or even bracelets. It serves as a reminder of the relationship and the promises exchanged.