High school long ago became a preferred setting for raunch-coms, but Seth Rogen and his confederates, anxious to break new ground, lower the bar (some would argue not only in age terms) to the elementary school level with “Good Boys,” a frantic farce in which three twelve-year old pals get involved in a series of slapstick adventures to prepare themselves for their first kissing party. Filled with coarse gags and foul language to contrast with the kids’ cheerful naiveté, it’s like a John Hughes movie (complete with dollops of sentiment) gone to seed, or a live-action version of “South Park”—a conceit that works sporadically but becomes tiresomely repetitive.

The trio, who call themselves the Bean Bag Boys, have been besties since kindergarten. Max (Jacob Tremblay) is a shrimpy, eager type, who’s introduced maximizing the boobs on a video-game avatar in preparation for trying to masturbate. Of course he’s interrupted by his goofy dad (Will Forte)—shades of “American Pie”—who promptly congratulates him on growing up before going off on a business trip and warning him not to touch his drone (you’ve heard of Chekhov’s gun; here’s Chekhov’s drone). Max’s real fixation, though, is pretty classmate Brixlee (Millie Davis), with whom the poor kid is utterly infatuated.

Thor (Brady Noon) is the abrasive member of the crew, but naturally with a sensitive side—his true love is singing, but his hope to score the lead in the campus production of “Rock of Ages” is dashed when he’s targeted as a sissy by class meanie Atticus (Chance Hurstfield) for refusing to take a swig of beer.

Finally there’s Lucas (Keith L. Williams), conspicuously larger than his friends physically but less anxious to seem cool. He’s a stickler for the rules, apt to protest his friends’ radical schemes and blurt out the embarrassing truth when they’re trying to construct a semi-convincing lie. He’s also harboring a sad secret, in that his parents have just told him they’re divorcing.

It would take considerable time—definitely more than it’s worth—to explain the series of misadventures our pint-sized protagonists get into on the way to that party, to which they’ve been invited by ultra-cool classmate Soren (Izaac Wang). Suffice it to say that in trying to learn how to kiss properly, they turn—after internet porn proves insufficiently informative—to spying on two older girls (Molly Gordon and Midori Francis) who don’t take kindly to the intrusion.

That results in the girls getting hold of the drone Max wasn’t supposed to touch, and the boys winding up with the girls’ bottle of ecstasy. The attempt to swap what each wants will lead to such wild and crazy bits of business as a paintball battle in a frat house, a dangerous attempt to cross an eight-lane freeway on foot, an encounter with a cop (Sam Richardson) who only wants to get home, and a wild bike chase that leaves one of the boys with a dislocated shoulder the others pop painfully back in place. There’s also a running gag about a clutch of sex toys the trio take from Thor’s parents’ closet and use in unintended ways, as well as volley after volley of F-bombs that are meant to be hilarious coming out of the mouths of babes. (Hey, we’ll make sure we get that R-rating!)

Of course, it’s inevitable that the boys have a falling-out and then come together again for a big hug in the end, even as each follows his own path in what amounts to a coda, the best part of which isn’t the “Rock of Ages” production by the addled drama teacher (Matt Ellis) that Thor stars in, but the montage of the vicissitudes Max endures in puppy-lovedom.

The three young stars are certainly energetic; it’s rather a shock to see Tremblay, after his quietly compelling turn in “Room,” encouraged by director Gene Stupnitsky to go into full manic mode, and Noon can be irritatingly smug, but the mostly laid-back Williams looks like a real find. Everyone else pretty much goes through the motions without much of an impression (Forte is amazingly bland), but Richardson aces his cameo, and Lil Rel Howery and Lina Renna have a few choice moments as Lucas’ parents, who are trying to be genially supportive even as they’re breaking up. Tech credits (production design by Jeremy Stanbridge, cinematography by Jonathan Furmanski) are what one would expect in this sort of fare.

There are certainly some laughs in “Good Boys,” but overall the Rogen team’s relocation of their usual frat-boy humor to the tween set proves a mixture of sweet and sour in which the latter dominates.