So in pretty much every porn scene the male performer is acting as a surrogate for the presumably male viewers at home. He becomes a kind of blank slate, stripped of identity, for the viewers to project themselves on. For this reason, scenes where the female performer actually moans the guy's name while they're fucking are extremely rare. I think directors think that it'll be harder for the viewers at home to put themselves in the guy's place if they hear a name other than their own.
I think it's pretty hot when it happens though. To me it indicates a genuine connection between the two performers and that the woman is enjoying herself enough that she can't help but deviate from the routine scenario. It's like she's so into it that she's breaking character, for lack of a better term. An example would be some old scenes with Mark Ashley and Rebeca Linares. They worked together pretty frequently and seemed to have developed a genuine rapport with one another. You got the feeling watching them, especially when she'd moan his name, that working together wasn't just a job for them. It was an experience, a happy reunion.
So any other scenes that fit the bill?