Starring Josh Zuckerman and Amanda Crew. Rated 18A.

Sex Drive raises some pressing questions for teen audiences. Like, which is more important, friendship or getting a “peppermint fattie” from a trailer-park hooch? Do real friends “twat block” other friends? Should one be more afraid of a) “a rolling brownout” or b) old-man scrotum spilling out the leg hole of a pair of shorts? The answer to the last question is, of course, b) since one can never fully recover from nut-sack exposure on that level of disgustingness. To answer another question: yes, a teen raunch romp employing man-glued gonch as a stunt prop can be stupidly funny and surprisingly sweet.

A filthier, finger-sniffing stepchild of Superbad and Fast Times at Ridgemont High, with a sex addiction to rival David Duchovny’s, Sex Drive is a road movie on a virginity-losing quest. The teen virgin is geeky Ian (Josh Zuckerman), who works as a giant doughnut in a mall while other teens commit crude pranks upon him. So when a hot blond he meets on-line calling herself “Ms. Tasty” asks him if he and his ’69 GTO Judge will cross the country for the night of his young life, the film has nonstop, gross-out, smut-fest fun answering that question.

Director-writer Sean Anders and cowriter John Morris, deadpan with the one-liners, bring along for the ride best friends Lance (Clark Duke), of the Judd Apatow school of pudgy guys who rock the ladies, and goth-cute angsty Felicia (Langley’s Amanda Crew). The three leads rise charmingly to the occasion, while James Marsden and Seth Green are inspired as, respectively, Ian’s demented brother and a sarcastic Amish dude waxing nostalgic about butt-fucking. Oh, and the real answer to that earlier question, kids, is c) the lady on the toilet who wants a hug.