Nipple clamp

[1] The first literary depiction of the nipple clamp was in 1790, in the novel Justine by the Marquis de Sade.

[7] If the blood circulation to the nipple is cut for too long there is also a risk of damage to the tissue and nerves.

Changes in skin colour can be used to determine the level of blood flow, which needs to be re-established regularly to prevent any permanent damage.

[8] When the clamps are removed the restricted blood flow rushes back into the nipples and releases oxytocin, a hormone associated with orgasm.

[4] The restriction and reintroduction of blood flow into the nipples can be painful,[2] and this is used as part of some BDSM activities such as breast torture.

They can be connected to a secondary attachment point such as a hook on a wall or a piece or furniture so that the wearer is unable to move without pulling on their nipples.

Carol Queen says that: "Some clamps cover a wider surface area and might be preferred by people with bigger nipples...

It has two short lengths of metal, joined by a spring to keep one end closed; in its simplest form, it is made of a crocodile clip.

Its serrated jaws are usually covered with removable rubber sheaths to protect the nipple from damage and to reduce pain.

These clamps are lightweight and adjustable[1] and their starting pressure is mild, making them suitable for beginners.

Typically, they have small 1 centimetre (0.4 in) rubber sheaths over the open ends for comfort, to protect the nipple from damage and to reduce slippage.

If this is pulled a mechanism inside the clamp moves the jaws closer together[6] and provides increasing tension.

[4] When they are applied to the nipples a spring hinge holds them in place under tension and provides a very high pain level.

[6] These clamps have small points of contact and hence their pinch is usually painful, especially on people with larger nipples.