[rhapsody]

I've done it a few times. I never thought it was something I would do until the first time it happened kind of by accident (I won't go into how it is possible to do something like that by accident), it didn't hurt at all and actually felt quite nice in a weird kind of way...

I agree that you can't really say 'that's disgusting and painful' when you've never even tried it. And no probably it isn't natural but then again you could say the same about oral sex among other things.