For their latest comic trick, Barbra Streisand and Seth Rogen go for something that neither has been known for over the course of their respective careers – cute. With “Guilt Trip,” they’ve made a holiday comedy safer for Streisand’s audience than for Rogen’s, a mild-mannered movie you won’t be embarrassed to take your mom to.

Well, not too embarrassed.

Rogen is Andy, an organic chemist who left his job with the Environmental Protection Agency to try to sell his environmentally friendly cleaner, “Scieoclean,” to K-Mart, Costco, Ace Hardware or whoever will have it. He’s struggling.

But to Joyce (Streisand), he is still “my perfect boy,” the apple of Mom’s New Jersey eye. Andy worries about his Mom, wonders why she doesn’t date. Mom wonders why Andy isn’t married.

“I’ve been to the dance, and now I’m tired,” the widowed Joyce tells him. “You’re skipping the dance altogether.”

A little revelation by her on a visit home gives Andy the idea to drag her along on a road trip, from New Jersey to San Francisco. Eight days in a car. Eight days in, thanks to Joyce’s frugality, a tiny Chevy Aveo, making stops in Virginia, Tennessee, Texas, New Mexico, Nevada and ending in San Francisco.

It’s a situation fraught with peril and pregnant with promise. Hear mom question Andy about “your problem with women.” Meet Andy’s ex-girlfriend in Nashville. Seek roadside assistance at a Deep South strip club (run by the formidable Dale Dickey of “Winter’s Bone”).

See Andy fail, time and again, at his meetings with retailers. Watch him ignore Mom’s always-sound advice. Hear her put a stop to his swearing. (“Enough with the language.”)

Streisand’s audience demands so little from her these days, and this Dan Fogelman (“Cars,” “Fred Claus,” “Crazy, Stupid, Love”) script demands even less. She’s played a Yentl. It’s time she tried a yenta, See Joyce in her active, over-scheduled life with her New Jersey coffee klatsch (including Kathy Najimy and Miriam Margolyes). Study her routine – dozing off as she watches TV and eats M&Ms in bed. Watch Joyce dive into one of those steakhouses where the meal’s free if you can finish a side of beef in an hour.

Even the broader moments have a muted, respectful comedy. Streisand is far more out-there and fun on those “Meet the Parents” movies. “Guilt Trip” is a comedy of gentle laughs and light moments, with both actors dialing down their personae to squeeze them into an econo-box of a car.

“Guilt Trip” is everything you’d expect in a mother-son road trip comedy starring the profane and pot-friendly Rogen and the wizened, smart-mouthed diva Streisand. And less.