Erotic electrostimulation (abbreviated erotic e-stim and also known as electrosex) is a sexual practice involving the application of electrical stimulation to the nerves of the body, with particular emphasis on the genitals, using a power source (such as a TENS, EMS, violet wands, or made-for-play units) for purposes of sexual stimulation. Electrostimulation has been associated with BDSM activities, and erotic electrostimulation is an evolution of that practice. Safety Electrostimulation, in general, can cause tissue damage or even death if misused. The most common problems arising from electrostimulation tend to be burns from lack of sufficiently wide surface contact, i.e. bad contact, between the electrode and the skin's surface. Even at relatively low current and voltage, there is also risk of interference with normal heart function (potentially including cardiac arrest), and this risk is higher for those who use an artificial pacemaker or similar device or who have heart conditions. Because of this, it is not advisable to place the electrical contacts in such a way that current passes through the chest cavity. The international standard on the basic safety of medical nerve and muscle stimulators advises "that stimulation should not be applied across or through the head, directly on the eyes, covering the mouth, on the front of the neck, (especially the carotid sinus), or from electrodes placed on the chest and the upper back or crossing over the heart". The standard also notes that "any electrodes that have current densities exceeding 2 mA/cm² may require the special attention of the operator". It imposes the following limits on the output parameters of stimulators (for therapeutic purposes): with a load resistance of 500 Ω, the output current shall not exceed 80 mA at DC 50 mA below 400 Hz pulse frequency 80 mA at 400–1500 Hz 100 mA above 1500 Hz for pulse durations less than 0.1 s, the pulse energy into a 500 Ω load shall not exceed 300 mJ per pulse, for longer pulses the above DC limit applies the output shall not exceed a peak voltage of 500 V when measured under open-circuit condition Erotic electrostimulation devices should avoid DC currents entirely, in order to avoid electrolytic effects. This is usually achieved through “biphasic” waveforms, in which each positive current pulse is followed by an equivalent negative current pulse. Devices with multiple channels (e.g. for several users or body regions) should have a small pulse isolation transformer for