The original, from a company called OhMiBod, has a cigar-shaped design that you plug into an iPod; the vibrating stimulus matches the beat of the song playing.
But now there's a pair of fancier new wireless versions, and, guess what? We test drove them both. (Boy, are we tired.)
Understand that it's not designed for rubbing out a quick one. It'll do in a pinch, of course -- it has a standard on/off switch -- but if you're going to use it with music, you'll need a half hour of "me time," minimum, so you can skip through songs to find the ones that work the best.
Once the doors were locked and it was just us, our iPod, and our Freestyle W, we found it to be a delightful experience. An added bonus: the music makes you less aware of your moaning. We found ourselves not caring if the neighbors heard us. Whee!
Our musical selection? We first employed a song with a heavy, thumping bassline: "The Hardest Button To Button" by The White Stripes. But while visualizing Jack White got us started on the right foot, the tune's bump-bump-bump-bumps were too far apart to get a good buzz going.
Imagine if your lover approached oral sex with the same intensity Meg White attacks a kick drum: bang, bang, bang, bang, stop, start, stop, start -- and you begin to see the problem.
Better were songs with a fairly constant drone of sound, alongside a good tempo -- keeping vibrations fairly continuous so you can use your hands to provide the rhythmic slide that gets the job done. "Sexy Boy" by Air was one of these; the "sex" in the title aside, it was the unrelenting synthesizer base that helped create our sonic boom.