You wouldn't expect a movie titled A Good Old-Fashioned Orgy to be this charming or likable, but improbably enough, it is just that. This is not to imply that it is not raunchy; this is a dirty, dirty little movie, filled with nearly non-stop sexual conversation, including verbal descriptions of sex acts rendered in cheerfully graphic detail. But it's all about how you approach these things, and somehow, writer/directors Alex Gregory and Peter Huyck make the movie salacious without making it either crass or mean-spirited. There is a sweetness to its ribaldry.

Eric (Jason Sudeikis) and his high school friends are still tight, fleeing New York over summer weekends for beach retreats and elaborate theme parties at his family's summer house in the Hamptons. But their days are numbered in their little paradise; dad has decided to sell the joint, which means that this year's Labor Day bash will be the final blow-out, one for the ages. Eric comes up with an appropriately hedonistic idea: an orgy amongst the friends, whose relationships have always been strictly (well, mostly) platonic. Everyone is against it, of course. Initially.

The film's greatest strength, particularly in those crucial early scenes, is that you believe this group--their byplay, the way their dialogue overlaps, their sense of shared history and inside jokes, they way they relate to each other both in the lines and in between them. (Some guys, for example, are just always referred to by their last names, no matter how close you get to them.) Gregory and Huyck have assembled a strong cast, and they all perform admirably; many of the characters are familiar types (the tightly-wound business guy, the overly-analytical therapist, so on), but those traits aren't allowed to entirely define the characters, or--most importantly--to make their closeness with the others less credible.

Those dynamics go a long way toward selling what could have been a sniggering, dumb-show premise. But the movie is about more than sex; there is some slightly subtle stuff on aging sexuality, for example (it's fleeting, but keener and smarter than the entirety of Hall Pass), and the picture goes, admirably, one step closer to the nature of Eric's relationship with his buddy/sycophant McCrudden (Tyler Labine) than most movies would. And though the subplot of Eric's budding romance with his sexy realtor (Leslie Bibb) is a little arbitrary, it's played with warmth by the well-matched duo.

Sudeikis has been doing good supporting work for a while now in films like Going the Distance and Horrible Bosses, and the picture is an ideal vehicle for his easygoing charm; standouts of the supporting cast include stand-up comic Nick Kroll, invaluable Apatow alum Martin Starr (his dry read of the not-as-funny-on-paper line "I would not have called that" generates one of the movie's heartiest laughs), and Michelle Borth, who has a wonderfully sideways sense of timing. Sudeikis's SNL castmate Will Forte and Bad Teacher MVP Lucy Punch also pop in occasionally, like switch-hitters brought in to add spice and push things just a little bit broader without doing any tonal damage.

As filmmakers, Gregory and Huyck are a touch amateurish; the establishing-shot-medium-shot-close-up structure of their scenes isn't terribly imaginative, although it is admittedly hard to get too slick with this kind of material. As writers, their instincts are mostly good, though they don't always see their scenes through, sometimes just throwing in the towel instead of fully mining a comic premise. But they don't blow it when it comes to the big set pieces--there is a visit to a queeze-inducing "sex club" in a mattress store that is quite funny (and gives us exactly the right amount of David Koechner), and they admirably do not cop out when it's time for the big climax--er, ending. A Good Old Fashioned Orgy is too shambling and laid-back to have the kind of fierce comic momentum that would lift it into the realm of the great screen sex comedies like Bob & Carol & Ted & Alice or Shampoo. But it's an enjoyable and funny movie all the same.

Jason lives in New York. He holds an MA in Cultural Reporting and Criticism from NYU.