It's the energy that sets a Shaun Costello 1-day porn wonder apart from the competition, and MAXINES' DATING SERVICE (incorrect punctuation displayed in the on-screen credits) is immediately recognizable as the master's work.

What fooled me is that Davey Jones (if IMDb's credit is correct) pops up early in the film as a gigolo-in-a-hurry, who I thought looked like Shaun but wasn't him. Similar to the way Woody Allen gets all sorts of people (from Jason Biggs to Kenneth Branagh) to impersonate him in his films, the "Shaun" role is ably filled here by another.

Premise is non-stop talker Ultramax as Jane Johnson on the phone complaining to her computerized sex provider (of the title) about bad service, and ordering up new humpers, preferably a brother-sister team, to fulfill her fantasies.

Running gag is that the computer is apparently on the blink, bombarding Ultra with arrivals of more & more sex workers to overload her libido. First up Eric Edwards and Juliet Jay as the siblings Dick and Dee Dee (I always liked the singing group by that name), immediately delivers incest, which seems real enough as the film progresses, even though the viewer at first will infer that they are merely pretending to satisfy a client's whim.

But before they can get down with Jane, Harvey Detweiler (Davey Jones doing the Costello impression) arrives, in a hurry, and insisting on humping Jane and running. She's paid Melanie by credit card, so has to get her money's worth.

Shooing Dick & Dee Dee into the bedroom, Jane services Harvey satisfyingly, with latter even throwing in a W.C. Fields impression. All the dialog is improvised, with plenty of dirty talk.

Meanwhile in the bedroom the siblings are doing what comes naturally, rendered amusing by a tasteless gag of Dick finding a long-lost marble in Dee Dee's vagina, recalling how their incestuous proclivities dated back to childhood games.

Back in the living room, Jane deep throats Harvey, but the eventual money shot is a fake (Ultra's mouth runneth over). Loud whirring noise of the camera motor detracts from the film's verisimilitude.

Farce continues with the doorbell ringing again, as an aggressive creep (unidentified thesp) with a pretty girl in tow (reliable Cindy West) insists on raping Jane, per her phoned-in request. She ordered it up via the computer a month ago, but here he is anyway.

Before you can say Alan Ayckbourn, Jane is juggling her ever-increasing roster of guests, putting the siblings together with Harvey (no longer in such a rush) in the living room, while she goes to the bedroom to get raped, as paid for. It's obvious that the cast's energy, ability to ad lib cleverly and a non-stop fast pace are what makes Costello's films click.

While no-name and Cindy are doing a job on Jane, the threesome in the living room are having childish fun trying to roll the marble back into Dee Dee's vagina as Costello's rude take on putt-putt golf practice. Of course they escalate to three-way sex. An orgy ensues when the rapist, Jane and Cindy join them, leading to plenty of real ejaculations.

With everyone tired out, the doorbell rings again, and Marc Stevens (hard to identify in dim light, but undoubtedly him) shows up as "the computer" walking stiffly like a robot and endlessly repeating "It's time to f**k", as poor Jane rues the day she contacted Melanie for computerized sex.

Except when the cast shuts up in later reels and gets down to routine humping, Costello has fashioned an entertaining porn comedy that holds up remarkably well after nearly 40 decades in the can. The Woodman coughed up a latter-day winner recently with MIDNIGHT IN Paris, so perhaps it would be fun to see SC direct a new porno harking back to his salad days.