First of all, nobody managed the “macho jerk guy who becomes a woman” movie thing better than Ellen Barkin in “Switch.”

Blake “Pink Panther” Edwards writing and directing, and the sexy Barkin — all gross and profane and genuinely puzzled about how women manage “these things” (breasts) and “all this HAIR” — was “on fleek,” as nobody said back in 1991.

The only problem with that comedy from the Golden Age of Body Switch Comedies? It sucked. Most did, and most still do — save for the recent French Netflix take on this “Man learns how hard women have it” version of the tale, “I Am Not an Easy Man.”

So that’s what “The Sex Trip” has working against it. A low-budget riff on the piggish man condemned to try being a woman for a while, it rallies for a few fun scenes, spends too much time in the toilet (literally) and suffers from a cast in which nobody makes you forget how good Barkin was in a bad film that covered the same ground almost 30 years ago.

Eddie Greenleaf (actor and British TV presenter Marc Crumpton) is a successful “How To” author. It’s just that his books — “52 Pick-Up” is one title — are about how to con women into sleeping with you.

He has “three “rules of engagement” he tells an appalled female TV interviewer — “‘Trigger her interest,’ ‘Play indifferent’ and then ‘Go for the kill.'”

He’s got the AMG Mercedes and Architectural Digest home to show for his success. But he’s a heartless jerk. And one night a homeless crone (Eve Sigall) confronts him on the way to a fashion show.

Women are just “notches on your bedpost…that’s a METAPHOR Eddie!” He needs to kiss her to “See the beauty in ALL women!”

He refuses, and that’s how Eddie wakes up equally-accented with the body of an Edna, “Eddie’s sister!” Jade Ramsey (“The Myth of the American Sleepover” and TV’s “The House of Anubis”) plays this version of Eddie, shocked and furious at this turn of events, but seemingly not so concerned that she spends day and night searching for the witch who put him/her under this spell.

Seriously, once Eddie/Edna has broken the news to piggish agent Steve (Louis Mandylor, funny in “My Big Fat Greek Wedding,” funny here), and they’ve made one trip to a homeless shelter in search of that witch, here’s what “The Sex Trip” script treats us to.

Edna goes in search of “some chick clothes.” See Edna test-drive her first bra, her first thong.

“Steve? What do you think?”

“Marry me!”

There’s her first gay hairdresser (Eric Carrigan) — “I’m gonna give you more waves than a Hawaiian surf competition!”

And her first waxing…wait, really? Followed by Edna’s first trip to the women’s locker room — gawk city, with all the naked, parading tattooed women looking like bartenders and/or strippers.

“Do you think you could rub some lotion on my back, please? Rub me REALLY good!”

A couple of things stand out and work here, starting with Mandylor’s playing of Steve as a bit on the fence on the whole sexuality thing. Homoerotic jabs at a sexist pig are easy laughs, and Steve’s a little of both.

“Hey Dreamboat,” he purrs to a potential bar pickup. “Not YOU, Shipwreck!”

And Edna’s first trip to a Sex shop run by sisters (Dahlia Tequali and Dia Tequali) is one long giggle.

“Welcome to Adult Warehouse, the paradise for sexually active adults” run by sisters they chirp in perfect sync. Need some help help getting “your Amelia Earhart on?” As in flying “solo” sexually? They’re experts. Check out their names — Dill and Doh.

The rest of “The Sex Trip” is a tedious ride indeed, from Edna’s makeover of a pert wallflower who runs a homeless shelter, Jess (Charlotte Ellen Price) to Ramsey’s scenes playing newly-outraged at the sexism the world shows him/her as a man-in-the-body-of-a-woman. Yes, Eddie will “grow” into a better man. Sure.

The script has few funny scenes or even lines. And as an aside to writer Marc Prey and co-writer and director Anthony G. Cohen, “first menstrual cycle” can be funny or gross, but generally not both. And vomiting on the camera lens (Edna can hold her liquor, but not Jess)? Almost never funny.

“Sex Trip” demonstrates that sometimes a tired idea is just that, tired.

MPAA Rating: unrated. sexually explicit

Cast: Jade Ramsey, Louis Mandylor, Marc Crumpton, Charlotte Ellen Price, Rachel Breitag, Natasha Blasick

Credits:Directed by Anthony G. Cohen, script by Marc Prey and Anthony G. Cohen. An Ammo release.

Running time: 1:20