MOVIE REVIEW : Playing Couples in ‘Threesome’ : A film about sexual confusion and role-playing shouldn’t be quite so grinningly content with itself.

The strange thing about “Threesome” is that it looks like a TV sitcom but it walks and talks like a soft-porn roundelay. It’s as if “Three’s Company” suddenly got a case of hot monkey love.

The threesome in question involves Stuart (Stephen Baldwin) and Eddy (Josh Charles), college roommates who couldn’t be further apart in temperament, and Alex (Lara Flynn Boyle), who, through a computer mix-up, ends up sharing a dorm suite with them. They hit it off--sometimes literally--in that seriously rowdy way that filmmakers always imagine college students behave.

Stuart is a business major but most of his business seems hormonally inspired: He’s a jock rake with an itch for Alex. (He thinks everything she does is sexy, even throwing food at him.) Eddy is a more languid and “sensitive” type, which, in movie-ese, means he’s sexually confused. Alex’s high-powered attempts to seduce him are rebuffed because, although he doesn’t let his dorm mates know it for a while, he’s attracted to Stuart.

Writer-director Andrew Fleming invests a lot of faith in these three: They’re featured in practically every scene, with occasional drop-ins by other students. It’s a strategy that only works if the characters are fascinating enough to sustain an entire movie and the hi-jinks in “Threesome” don’t sustain. It becomes “Tiresome.”

Despite the likability of the three actors, Stuart, Eddy and Alex never achieve fully human status. Fleming zeros in on the sex and the romance but keeps out just about everything else that might allow us to connect with them. (“Carnal Knowledge” had the same problem.) We don’t get any sense of what it really means for these three to go to college--as if it would be too “square” to actually deal with how they were affected by their studies. It’s all on a paper-thin “personal” level. That’s what’s sit-com-ish about it.

A movie about sexual confusion and role-playing shouldn’t be quite so grinningly content with itself. There’s no particular terror or upset in the lives of these three. Alex’s rejection, Eddy’s wavering, Stuart’s rollickings are all experienced on the same level as a fatuous coming-of-age scenario. The sex scenes--such as Alex writhing on Eddy’s library desk or talking to him on the phone while being made love to by Stuart--seem shoe-horned into the movie in order to make it sparkle for the youth market. “Threesome” gives raciness a bad name. It’s almost enough to bring out the prude in you.

Besides “Carnal Knowledge,” “Threesome” has its other influences and, in one of its more shameless scenes, we see one of them. Eddy is shown watching a movie--described only as “an old French film about two men who loved the same woman.” That Truffaut’s “Jules and Jim” should be tossed off in this way is a measure of this movie’s Liteness. Should we be thankful Eddy wasn’t watching “Citizen Kane,” a classic “about a newspaper big-shot”? Or “Psycho”--a movie “about a guy and a shower”?

* MPAA rating: R, for strong sexuality and sex-related dialogue. Times guidelines: It includes lots of sexual situations of all persuasions . ‘Threesome’

Lara Flynn: Boyle Alex

Stephen Baldwin: Stuart

Josh Charles: Eddy

Alexis Arquette: Dick

A TriStar Pictures presentation. A Motion Picture Corporation of America Production in association with Brad Kevoy and Steve Sabler. Director Andrew Fleming. Executive producer Cary Woods. Screenplay by Andrew Fleming. Cinematographer Alexander Grusznski. Editor William C. Carruth. Costumes Deborah Everton. Music Thomas Newman. Production design Ivo Cristante. Set decorator Tim Colohan. Running time:1 hour, 42 minutes.

* In general release throughout Southern California.