I financed my travels around the world working odd jobs, one of which was a labourer on a construction site in London in the middle of winter.
My job was to sand the ceilings with an orbital sander. This is a machine that mimics the circular action that you would make with your hand if you were sanding - it just vibrates very fast on a flat plane.
Anyway I was working away and its gets very tiring holding this machine against the ceiling while standing on a ladder, so I had to take a rest quite often. On one of the occasions as I brought my arms down I left the machine on for a bit longer than normal and while it was humming away it brushed up against my groin region. Whoa! Hoo Boy I realised here was some potential!
I took a quick look around and being on my own in the room succumbed to the experiment. Because I was wearing very heavy clothes for the cold the extreme action of the tool is dampened quite a bit but with the pad against my jacket over my groin area, it only took about 15 seconds!
Perched on the ladder I didn't even have a full erection by the time I had an awesome knee buckler of an orgasm. I made a complete mess of myself in my pants and nearly fell off the ladder. Just imagine how difficult it would have been trying to explain to an emergency doctor how I came in my pants and broke a leg or something!
I hadn't expected it to be that good and made an absolute pig of myself by passing the day with one orgasm after another - I had about 6 or 7.
I figured that to minimise the mess I would put some toilet paper in my pants, it worked but unfortunately my newfound pastime had a serious drawback.
A cock was not built to be vibrated by an industrial strength vibrator and it was starting to get a little sore. It was only when I went to have a look in the loo that I realised that the extreme vibration had cased a very small but quite painful abrasion on the shaft of my cock. This put paid to all masturbation and I mean all. I couldn't even use my old tried a tested methods until it had healed.
So for those of you who want to give it a try, (and I think it would work just as well for the girls here too), I would use a pillow or something suitable to dampen the vibrations and possibly use a lube too. And lastly don't over do it, this method although it gets a very high rating on the intensity scale is not really suitable for prolonged use.