A leash or lead is a length of rope, leather, chain or other flexible material ostensibly for restraint or control. Most leashes attach to collars or body harnesses, while others loop directly around the person's neck, wrist, ankle or sometimes around the male genitals or female body piercings.
The most common leash used on a human is one with a clip at one end and a loop of the same material at the other. Commonly made of leather (occasionally braided for extra flexibility) but sometimes of nylon webbing, small-linked chain or rope. Many people use a strong dog leash, especially a black leather one. Typical length in total is between one and two metres.
The submissive's collar, leash, and restraints are highly symbolic. Being led on a leash makes many submissive people feel comforted and gives them a strong sense of belonging. Some experience humiliation but that doesn't stop it being a positive, sexual experience. Leading a submissive on a leash can make a dominant very proud of their partner and give them a strong sense of ownership and responsibility.
Leashes are most often used in private or in a secluded public place, or sometimes in public but discreetly so as not to be obvious to others. Sometimes, a leash is used very openly and publicly, especially in a scene club.
At a club or play party, D/s players often prefer formal etiquette and will use a leash as part of this, to signify that the submissive is not single or, if the leash is held in their mouth, that they are not available for conversation.