By Chris Lee
May 05, 2015 at 11:49 PM EDT

Since January when The D Train premiered and was quickly snapped up for theatrical distribution as one of the buzzier titles at the Sundance Film Festival, the scene has been the indie dramedy’s primary talking point: a romantic hook-up between Jack Black’s bumbling suburbanite character and James Marsden’s Hollywood hunk.

In The D Train (which arrives in theaters Friday) Black portrays Dan Landsman, a straight-laced small-town dad organizing his high school’s 20th anniversary. In a bid for popularity, he becomes fixated on a crazy idea: that persuading Marsden’s character Oliver Lawless—the campus golden boy who moved to Los Angeles in search of acting glory but whose most illustrious credit is a Banana Boat suntan lotion commercial—to attend the reunion will win Dan the cool points he’s been denied since adolescence. So he tracks Oliver down on the Sunset Strip. But after a debauched evening of cocaine, pain pills and tequila shots unexpectedly yields a tumble between the sheets, Dan’s conception of himself abruptly shifts on its axis.

Rather than aim for the kind of “Whoah! They’re gay!” comedy of discomfort one might reasonably expect from a movie starring two of Hollywood’s most steadily employed movie stars, however, The D Train uses the one-night stand to underscore the characters’ flawed humanity. According to co-writer/directors Andrew Mogel and Jarrad Paul, a pair of veteran TV and movie writers making their directorial debut, the operative idea was to make a kind of anti-bromance. “We didn’t want it to feel like sketch comedy,” says Mogel. “We wanted it to be a real character study and treat it honestly and not jokey in any way.”

Adds Paul, the movie isn’t even “about” their romantic assignation, per se. “Obviously, that’s a big moment and that’s what steers the story,” he says. “But it’s the aftermath that’s more interesting than the actual moment anyway. Like, Dan’s unraveling happens inside his head Suddenly, his world is more interesting.”

That being said, thanks to vagaries of the independent movie’s shoot, plotted around Black’s busy schedule over 21 days in New Orleans last year, the sex scene wound up being the last thing the filmmakers shot. And while it leaves most physical details to the viewer’s imagination, the co-directors still made sure they had plenty of coverage once the cameras started rolling.

“We did it all night,” says Paul. “We made them go at it probably more times than they were comfortable with. In editing, we realized we had more than what we needed. Less is more.”

The key to getting Marsden and Black in the right mood to passionately make out and drop trou? “A lot of shots of whiskey. They drank some alcohol,” says Mogel. “It just ended up being the last scene. It built up and there was lots of tension.”