I have a few, but the one that gets the most use by far is my Womanizer Premium air pulsator. The company's name isn't exactly the best, but the products are very effective. I believe this exact model is discontinued, but there is a newer version available. If the name is too uncomfortable there's also the WeVibe Melt. It's a different brand, but the same company. Just as a disclaimer, I don't personally have a Melt, but it's very highly regarded.

Edit: By the way, the manufacturer is having a big sale right now.