Suction cups and vacuum cupping sets are based on the oriental method of using suction to pull impurities of the body through the surface of the skin. In BDSM scenes they can be used on a variety of parts of the body; breast, nipples, penis, even the buttocks to induce a range of sensations in someone from the pleasurable right through to extremely painful!
Suction cups are usually supplied with a small hand pump to remove the air from the glass and attach it to the skin. The more air removed, the tighter the cup will attach itself and the more intense the sensation. Depending where it is placed on the body and the amount of suction applied, the resulting sensations can range from mild discomfort to extreme pain. On removal the suction cup leaves a temporary "hickie" mark on the spot where it it was attached.
The fire cup is based on the same concept as the vacuum pump cupping set, whereby air is removed, but here, the heavy, thick heat-tolerant glass globes are used. By using the flame from a candle or lighter held under the opening of the globe or by heating the cup itself, the air is heated and expands inside the cup. Then it is immediately set on the skin area. As the air inside the cup cools, the skin is pulled into the glass globe! With practice the fire cup provides a highly visual experience and is sometimes used as part of public BDSM performances.
Nipple suction cups
Nipple suction cups are are small suction devices designed to increase circulation and pull the nipples to make them fully erect. This stimulation can be pleasurable for many women, and can even lead to orgasm. They range from simple, cheap plastic nipple covers to designer stainless steel cylinders. Wearing nipple suction cups can be pleasurable in itself, but they can also increase nipple sensitivity once they are removed. They are a gentler alternative to nipple clamps.