Yeah I can self suck with a bit of effort, although to burst peoples bubbles I would say its not that much fun.
It looks hot no doubt, my wife thinks its amazing - especially when she licks at the same time. However been bent over like that is uncomfortable and actually very hard to breath!
Its a bit like trying to tickle yourself, it just doesn't have the same effect unless someone else does it.

I have seen 2 videos Wildhoney refers to:
(Xtube login required)
self suck & fuck1

self suck & fuck2

I could probably fuck myself in the ass but really whats the point? The angle is all wrong and I can't imagine it stimulates the prostate gland which I guess is the point.