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“Sleeping With Other People” opens Friday at Star Cinema. R, 1:35, three stars out of four.

“Sleeping With Other People” is a love letter to New York romantic comedies, or at least a well-crafted sext. Writer-director Leslye Headland previously made the delightfully mean “Bachelorette,” where underneath several layers of nasty behavior hid a rather earnest ode to female friendship.

We don’t have to dig that far down to the sweet core of “Sleeping With Other People,” although this is a film where sweetness and raunchiness go hand in hand. For example, in one scene Jason Sudeikis is sincerely trying to be helpful to Alison Brie when he uses the top of an empty juice bottle as a prop to illustrate how to properly pleasure a woman. It’s a scene that may be the best, or worst, product placement ever.

Sudeikis and Brie both play perfectly likable, perfectly despicable New Yorkers who can’t stay faithful to their partners. Sudeikis’ Jake is your typical bed-hopping lothario, making up for being a late bloomer. Brie’s Lainey is more of a monogamist, cheating on all her boyfriends with the same man, a perfectly charmless heel of an ex-boyfriend (Adam Scott) who retains a tight psychosexual hold on her.

At a sex-addiction group, reconnecting years later after a bad first encounter in college, Jake and Lainey decide to give friendship a shot. As their friends (including the very funny Jason Mantzoukas and Natasha Lyonne) disapprove of their screw-the-rules ethos, Jake and Lainey draw ever closer, united in their bad behavior. They get each other’s dysfunctions, and Brie and Sudeikis generate real chemistry and affection, even as they play characters we would never ever fix our friends up with.

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Headland’s clever, pop culture-savvy, rat-a-tat dialogue about love and sex keeps “Sleeping” moving forward at a brisk clip, and she’s eager to twist and turn the rom-com structure like a balloon animal without letting it deflate.

Eventually, we’re pretty sure these two are going to end up together, but Headland is putting enough body English on the genre’s tropes that we think maybe it’ll cross that line. In fact, Headland finds a perfect, bittersweet ending for Jake and Lainey — only to blow past it for another 20 minutes towards the ending we can all see coming.

But, of course, it turns out that’s what we wanted all along, and “Sleeping With Other People” sends us home with a fizzy joy, some memorable lines to quote, and a deep-seated reluctance to drink juice straight from the bottle again.