SWEETHEART raises the thorny question: how hard does an actress have to work to earn top billing? Susan McBain humps her little heart out, and then some, in the leading role, but cutie Jean Jennings, little more than guest star, is #1 billed.Then, as today, it has more to do with box office draw than anything else, and Jennings was a huge hit in THE DEFIANCE OF GOOD and AUTOBIOGRAPHY OF A FLEA. However it is misleading to list her as starring in SWEETHEART -she doesn't even remove all her clothes (playing with her top on throughout, as if she had some scars or bruises to hide) until the final reel.Hoary melodramatic plot line (which male lead Wade Nichols explicitly mocks at one point) has McBain an heiress married to a handsome but unsatisfying hubby (Nichols). Opening wakeup scene shows him refusing to service wifey in the morning, and he's too tired to have sex with her after work.Antagonists are a pair of ridiculously inept burglars John Black (providing mixed combo content) and the beautiful Jennings. After Nichols drives to work, they invade the McBain/Nichols mansion Black's been casing, with the doors conveniently left unlocked.McBain is upstairs masturbating, as she flashbacks memories of both boy friend Jack (Philip Marlowe) and her hubby humping her. The burglars are delighted to find her with vibrator in hand, and proceed to rape her but ultimately delight the horny housewife.Director "Bo Koup" (whose creativity ended after he selected his pseudonym) insists on flashy cross-cut editing throughout the film, detracting from its erotic impact and proving to be mighty distracting. Worse yet, it's done incompetently, with very poor shot matching and other screw-loose errors; for example, after a money shot in one scene of McBain taking it doggy-style, Koup shows us the ejaculation from various angles, and then cuts to McBain still in motion as if the pumping were still occurring.While the poverty-row house invaders are working on McBain, Koup inter-cuts a scene of lovely Terri Hall (with too much rouge on her cheeks, as always) humping a mystery man -whose face is not shown. Obviously it must be Nichols cheating on his wife, and later on, we're shown that yes, it is him. More lousy shot matching has Nichols oddly wearing a cock ring above his testicles in rear-view closeups, but it's not there in the master shot.Terri, who is McBain's cousin, evilly plots to kill McBain so that she & Nichols can live happily ever after with all the inherited fortune. Nichols acquiesces, though even he wonders about the efficacy of sort-of scaring her to death. Instead of the usual DIABOLIQUE gimmick, they're going to "shock" McBain by presenting her with a Terri/Nichols humping tableaux at tonight's dinner party which supposedly will prove too much for her weak heart! I know we fans of storyline porn are hard up, but this is lamesville.McBain has become pretty chummy with the burglars, who are now getting ready to pack up her jewelry, cash and artwork and make their getaway. But wouldn't you know it, good old Philip Marlowe (we could have used the detective rather than the unappealing porn thesp) shows up insisting on a quickie with McBain. She can't shoo him away no-how, so they hump in the backyard, finally interrupted by an impatient Black, brandishing his revolver.He chains the two of them to separate trees, but even though Jennings appears wearing a leather bikini in Dominatrix mode and brings a big whip, there is little s&m, just more sex. With Hall and Nichols arriving early for the party, the rest of the film is a tedious orgy, mixing and matching the cast of six out in the backyard.I was impressed with both McBain's histrionics in a virtually unplayable role, as well as her all-stops-out sexual performance. Not only do all the male leads have sex with her but flashbacks present two separate gang-bangs from her past, one featuring the extremely obscure big-dicked performer Bill Cort who McBain rides in a barber chair. She also contributes several double penetrations -what a trouper! Film's climax and a postscript are both very silly, poorly scripted and poorly played. Other than McBain, the rest of the players clearly decided early on that this was really a wall-to-wall sex exercise and even Nichols is not up to his usual acting standard. For film students, the aforementioned "fancy editing" technique should serve as a warning considering how such antics can ruin a movie.