Alright, I can actually do this. You have to be very limber, and it helps to be lean, too. But it takes a long time to get to be able to.
But, sadly, it's not nearly as pleasurable as you might think. Autofellatio is only wonderful to those who haven't done it yet. Sucking your own dick may sound like the best thing ever, but it's really more like trying to tickle yourself. It just isn't the same as somebody else doing it. When you do it to yourself, you can feel it on your tongue and your mouth, so you know it's you. That instantly takes a lot of the pleasure away from it.
While I can do it, yea, it's nothing to be overly proud of. I masturbate "normally" anyway, because it feels better.