Erotic electrostimulation, also called "E-stim" or "electrosex", is a human sexual practice involving the application of low current electricity to the body using a special apparatus (such as a TENS unit) for purposes of sexual stimulation. Erotic electrostimulation has been particulaly associated with BDSM activities, although its use is becoming more "mainstream." Different sorts of electrodes are used for erotic electrostimulation, such as specially designed vaginal plugs, vulval skin electrodes, anal plugs, cock rings, catheters, cock-and-ball torture (CBT) boards, etc. Electrodes usually require an electrically conductive gel to be applied before use. A large variety of devices are available.
Electrostimulation can be tissue damaging or even potentially fatal if misused. The greatest risk is electrocution that can stop the heart even at relatively low currents and voltages (eg, a 9-volt battery in an ohmmeter which killed an incautious, indeed reckless, US Navy sailor taking an introductory electrical course). Mains-powered equipment should generally be avoided, as internal faults will be much more dangerous than the same fault in a battery powered device. Devices should be battery powered, isolated from mains supplies, as well as current-limited.
It is important to keep the path of current away from the neck, head, and particulaly the chest area --- a difficulty when participants may be tempted to stimulate the sensitive areas of the breast. The general guideline is to keep it below the waist. Permanent or temporary body piercings should not be connected to any electrostimulation device, since their small contact area can easily result in burns. Like all electrical devices, TENS units should be kept away from water, and manufacturers' instructions should be read and strictly followed. A little common sense goes a long way, though commn sense in electrical matters can be odd to the uninformed. As with all sex toys, it's important to educate oneself on their use, problems and effects. Especially with regard to BDSM play, participants should understand of the level of play before starting a "scene" using any form of electrical device.
Never use electrostimulation on someone who has a pacemaker, insulin pump or other electrically operated medical implant. Do not use on anyone with a history of epilepsy, a history of strokes or seizures, heart disease or nerve damage. Pregnant women should not use electrostimulation at all. If any doubts exist concerning the risks associated with electrostimulation, do nothing and consult a physician before proceeding.
References to electrostimulation can be found as far back as 1745, before the invention of the battery and when the only sources of electrical current were Leyden Jars and electrostatic generators. In the mid 18th century everybody who had heard of it wanted to experience an electric shock. "Electric kiss" machines were created so that one person, generally sitting on an insulated chair, could be charged up then kiss a grounded partner. A popular salon amusement at the time, this type of apparatus undoubtedly found more private uses.
Erotic electrostimulation in its modern context first came into existence during the 1950s with the introduction of a device called the Relaxacisor, which was originally designed to stimulate the muscles of a person using electrical currents while relaxing (as a means of "passive exercise"). Such devices are still in use today and are known as EMS (Electro Muscle Stimulation) units. They are also used in 'weight reduction' schemes outside of medical contexts.
Some people found alternative uses for the Relaxacisors by placing the contacts on sexual parts of the body. By the 1970s, medical TENS (Transcutaneous Electrical Nerve Stimulation) units were being used for erotic electrostimulation, too. However, neither the EMS or medical TENS units were ideal for erotic purposes, and in the 1980s the first devices manufactured specifically for erotic electrostimulation became available.
Types of devices
Medical TENS units are designed to produce temporary pain blocks in nerves (for pain management), and though they can be used for erotic electrostimulation purposes, most people don't find the sensation they produce especially erotic. Medical EMS (Electro Muscle Stimulation) units are quite different and are designed to cause muscle contraction (eg, in the thighs) and are also far from optimal for erotic use.
Body toning devices
An increasing number of "body toner" or "electro massage" -type devices are being marketed directly to consumers. Like medical devices, these types of devices were not designed as sexually-oriented equipment. They vary widely in quality and capabilities and most have a power output that is often too low for erotic use.
Some people may try to craft a "homemade" electrostimulation device, or adapt or modify commercial products that were never intended for electrostimulation of the human body. Unless the designer and builder is both graduate level informed in biomedical electronics and very well insured, this is not a good idea. These are dangerous practices; such improvised devices can easily inflict permanent damage or death and should not be used.
Erotic electrostimulation devices
Erotic electrostimulation devices are specifically designed and manufactured for erotic use on the human body. The first analogue devices became popular during the early 1980s, and later during the 1990s digital devices also became available. Both types usually allow for adjustments of frequency and power output levels. The price of erotic electrostimulation units varies according to the design and sophistication of the device.
There are three major manufacturers of erotic electrostimulation units in the United States, two in the UK and several other around the world. Different manufacturers use different connector types, but adapters are available to allow electrodes made by other manufacturers to be safely and conveniently used with other erotic electrostimulation devices.
Medical gel electrodes are commonly used and have a 0.080 inch jack (and may require a "banana-to-pins" adapter to convert a standard 4 mm banana plug into a 0.080 inch TENS pin lead). A "banana-to-snap" adapter can be used to connect a standard 4 mm banana plug leadwire to devices having 4 mm snap studs. Adapters are also available to connect electrodes with 2.5 mm plugs into devices which have 3.5 mm connectors. This makes most erotic electrostimulation devices interchangeable.
Lubricants containing silicone should generally not be used since silicone is an insulator and hence reduces conductivity. Choice of lubricant is important, too; compatibility with the material of the electrode accesories is important, as well as desirable conductive properties, which can maximize the strength and quality of the signal.