Starring Dane Cook and Kate Hudson. Rated 18A.

Raunch and romance have gone together ever since There’s Something About Mary and that baby-batter hair gel. Yes, thanks to the Farrelly brothers, and their illegitimate child Judd Apatow, moviegoing couples can now get grossed out and goo-goo–eyed at the same time.

My Best Friend’s Girl puts an ugly twist on that formula by upping the asshole factor. And by asshole, I mean Dane Cook. The ultracrude comic plays on his stage persona with Tank, a guy friends hire to emotionally terrorize their exes: when he gives them the worst night of their lives, they go running back to their old boyfriends.

Whether he’s talking to his date through a lap dancer’s butt cheeks or rapping along to “Pop That Pussy” a little too enthusiastically, there’s something unlikably creepy about our romantic hero—especially when things turn sappy.

Dustin (Jason Biggs) hires him to offend wholesome Alexis (Kate Hudson) in the hopes she’ll come grovelling back. But Alexis sees through Tank’s shtick and decides to explore her wild side with the bad boy. He finds his soft and cuddly side in the process.

Screenwriter Jordan Cahan and veteran director Howard Deutch (Pretty in Pink, if you can believe it) never find the right cocktail of sweetness and depravity. The exception is Alec Baldwin, as Tank’s dad, who manages to brag to his son about “bangin’ women since you been laminatin’ pictures up in the bathroom”, then convincingly pledges his love for his late wife.

The film’s few laughs centre on a wedding from hell, where a Jí¤ger-fuelled Tank smokes Afghan “Kush” with the kitchen help and propositions the mother of the bride. But sorry: the same guy who drops his pants and yells, “C’mon, it’s not going to suck itself” at a 60-year-old celebrating her daughter’s wedding day isn’t quite convincing when he woos Hudson’s Alexis with a corsage and a limo.