"Great Sexpectations" is a remnant of the age of story-driven adult films that were actually shot on film. The story is complex and leads to lots of couplings (and triplings), but the delivery is hilarious, either intentionally or unintentionally, revealing a lot of foibles of sexuality not usually addressed in modern porn.
Many of the funniest lines are delivered in so deadpan a manner, its easy to imagine industry insiders discussing the quirks of their business -- making some parts of this film seem to be the adult equivalent of "Seinfeld" -- a porn about "nothing". (to paraphrase: "Let me tell you how we do it in films. When you feel yourself starting to... pull it out and spray it all over her... _That's_ how we do it in films.").. Even without the various interludes, the story progresses and amuses.
Crocker, a legendary porn director must deal with his own wistful connections to his former wife, making him unwilling to star in his own films as he used to. He must deal with an industry diva who wants to undercut his creative control, young up-and-comers who want to tag along to become the next big thing, including one young sweetheart who is only going to perform anal because her mother told her to. On top of all this, Crocker must deal with an unconventional producer who offers his wife for auditions, and demands that Crocker capitulate to Marilyn and to to Frances' mother. In the end, it all comes together, so to speak.