One time, back in 1992, when alone on a late night in my office, rather than usual occasional manual masturbation, I thought, "I wonder if controlled electrical current on the genitals could bring about orgasm?". Next time working later, I brought some things along with me that I could experiment with.
When I did so, I naively thought at first I might have been the "only one" to have tried this kind of thing. Or at least one of very few people to try it. What a misconception.
Anyway, I used a little HO gauge train transformer and two wires to stimulate my genitals by wrapping a wire around my glans, or just below it, insulated by a little piece of damp paper towel, and scrotum in a cup of salt water with the 2nd wire imbedded in the bottom of the cup.
I gingerly turned up the power level until I felt something. It was tremendously pleasurable. After very little time, a strong ejaculation happened as my heart raced. "This is really worth pursuing," I thought.
Later, when the internet became available, a few years down the line, I was able to research and found a couple of e-stim sites, showing me that I was far from a "loner" in this and I learned a lot about more advanced methods. I've yet to try 'stereo-stim' - two channels, but after twenty-five years I'm about to adapt it little mini-sound speaker amplifier for this. Always new things to try in the field!
I've gotten a lot of info from Smartstim.com and its predecessor websites. I've never bought commercially made equipment but prefer to adapt other items to accomplish my goals.
I still have that old train transformer, although the power control switch is a bit "jerky" and jumps from very low power to much higher without warning so I've stopped using the relic.
But what was YOUR initial experience with e-stim?