South African sex comedies are rare on these cinematic shores. But when you travel “Around the world with Netflix,” you never know what you’ll stumble into.

“Do Your Worst” is a laugher about a struggling single actress making bad decisions into her 40s and the bestie who resents her for that one role that made her famous. It re-pairs two of the stars of the South African TV series “Still Breathing,” Shannon Esra and Kate Liquorish, who click as a comic duo in a rom-com/sex-com of the “Close but no cigar” variety.

It begins with David Attenborough imitator voicing over a woman in Neanderthal makeup barking at her director about a busted take. Our heroine, seen in her natural environment, is what anthropologists would call “a hot mess.” And our story, we are told, takes place in Johannesburg, “an imperfect city — unlovable — but lovely in its own way.”

Sondra (Esra) and Carla (Liquorish) are each-other’s “ride-or-die,” the same age, sharing the same short temper. But one’s still having to audition for commercials, even though she was “famous” for a show twenty years before. She’s never taken a steady job, lives in her parents’ former house, which they let her stay in when they moved to more lush digs, and is unmarried.

Carla lives vicariously through her, seeing as how Sondra “stole” the role that Carla was up for, which would have changed her life. Carla insists on blow-by-blow accounts of her friend’s sex life with “f— boys,” guys given to sending her you-know-what pics.

Descriptions of this or that bloke’s “junk” uses actors and props for comparison — “Danny DeVito with marbles? Chris Hemsworth with boulders? Tom Cruise with GRAPES!”

Sondra knows things aren’t working, but Carla never tires of bucking her up before auditions, and reminding her of how this or that not-quite-right relationship isn’t going to work out.

Then judgmental Mum (Dorothy Ann Gould) and silent Dad show up to announce that they’ve lost most of their retirement savings to a con-artist relative. They’re going to need the house back. It’s time for Sondra to grow up and “get married,” because what else is she qualified to do?

Let down by her latest “boy” on her 40th, drunk enough to kiss Carla’s husband (Rea Rangaka) when she isn’t looking, about to be homeless, is that “historical reenactment” role for the BBC the thing that’ll turn it around, or just another milepost on her path to utter humiliation?

The silliest waste of time screenwriters and directors are hooked on doing these days is deciding their stories need to be broken into “chapters,” which they give cute names.

“Part 1: Sondra’s Worst Day…Part 4: Definitely really Sondra’s Very Worst Day,” and so on.

Stop it.

The funniest scenes here are of Sondra doing her “difficult” on the set shtick, facing every fresh career degradation with a twitch and bottled up fury, which she might unleash when she gets back to the home she’s about to lose.

There’s a “Brazilian” scene with her beauty-parlor-manager sister (Sharon Spiegel Wagner) that’s got a hilarious pay-off, one referenced repeatedly through the rest of the movie.

Wayne Van Rooyen plays the sensitive contractor hired to fix up the bathroom before the house can be rented out, a chivalrous chap eager to help a screen star (in his mind, anyway) in distress.

Of course we can see where this is heading. The trouble is, not enough that’s amusing happens along the way. Tired bits with cellphone mix-ups and further evidence of how Sondra is just “the worst” don’t deliver that celebratory cigar, much less light it.

But Esra and Liquorish are balls-out in some of their scenes together. They always click, and are at their funniest when they’re fighting, indulging and humiliating each other.

More of that, please.

Rating: TV-MA, sexual content, profanity

Cast: Shannon Esra, Kate Liquorish, Wayne Van Rooyen, Rea Rangaka and Dorothy Ann Gould

Credits: Directed by Samantha Nell, scripted by Zoë Laban. A Netflix release.

Running time: 1:31