In some of Rocco Siffredi's porn movies, you see once in a while Rocco slow down with his cock inside the woman's ass and bend his cock at some weird angle or just try to stay inside the woman's ass while he reaches somewhere or changes his position on her.
And this kind of thing happens not because Rocco is fooling around and doesn't know how to fuck. It happens because there is another sexy lady in the scene distracting Rocco with her pussy, tits, lips, or ass. Rocco is reaching out to her, while he is still banging the other lady's ass.
I think this kind of a break in the monotony of fucking rhythm makes the fuck more interesting to watch. Such a break in the fucking rhythm doesn't make sense, when the guy is alone with the lady. But when there is another sexy lady distracting the guy from his anal fuck, then his break in the anal rhythm looks logical and hot.
This kind of distraction from the second sexy lady lets the guy pose in all kinds of hot anal positions with his anal lady in a way that looks logical and hot for the viewer to see. I think this a good way to break up the usual monotony of a fuck and make it more eventful and more interesting for the viewer to watch.
Showing off on purpose doesn't look good. But 'accidental' showing off of weird, acrobatic, and unusual anal positions often looks pretty hot to the viewer.

Edited by - Dan on Mar 27 2012