I have one that I've used before. The biggest problem with them is that you have to use lube, which = messy. When I wanna handle my business, it's usually like a Spec-Ops mission. As fast as possible with as little evidence as you can.

When you use those things you have to get it out of your hiding spot, get the lube, do your business, clean yourself, clean the item, re-hide the toy. This all leads to about a 20-30 minute ordeal which isn't really worth the 4 minutes of entertainment.