If you put a ping pong ball fully up your anus and then you sit down it completely disappears and then after a few hours you completely forget about it. The thing is though, and here's the fun part, the next time you go to the bathroom it ejects itself with force and it makes this crazy popping wine cork sound, like something out of a movie. You can do up to 3 balls at a time. Anyway I use this trick at restaurants and movie theater bathrooms and I make sure to eject them when other people are in there with me. They don't know what's going on in there but they absolutely love it, it's such a cool noise.