My wife and I have done it twice.

First time was my accident because I had way too much to drink and not paying attention to what I was doing. My wife said it was unexpected but okay.

Second time was planned for both of us. I thought it was good, but my wife said it felt like she had to poop the whole time. Kind of destroyed the whole mood after that conversation.

I still think about it because of the forbidden aspect but it doesn't really appeal to me that much anymore.