Most people have played with some kind of vibrator. Do you remember the first time you applied one (or had one applied) to your genitals? Felt pretty good didn't it? At the least, it was something new and different. Electrostimulation is a lot like that only even more unique. It's a wonderful way to add some new fun to your sex life. The proper electric current causes both the stimulation of nerve endings and involuntary muscle stimulation. Both of these effects can be combined for a very erotic experience. Some people also use electrostimulation for S&M play. It's an excellent way to explore the pleasure/pain boundary without the usual risks of damage or lasting pain to the body. It can be precisely controlled and when it's over, the one submitting to the stimulation is none the worse for the experience (something that cannot be said for most kinds of S&M play).