After 15 years as a top porn actress, Angela White’s crowning achievement was showing what happens after sex.

“Angela 3” featured White and fellow veteran Manuel Ferrara having sex for 93 minutes straight without a single cutaway. But instead of fading to black when they were spent, the camera kept rolling for an unprecedented 17 minutes while the two chewed over what they had just done as if they were in couples therapy.

“It was way more hardcore than all those extreme physical acts,” White told The Post. “Delving into your emotionality and opening yourself up like that. At the end of the scene, I cried, it was so emotionally touching.”

“Angela 3” is becoming a rarity in the porn world: a star-driven sexual extravaganza that ignores the industry’s mandate to pack as much fornication as possible into 30 minutes or less. More shocking, it broke probably the last taboo in porn by showing two people engaged in — gasp! — emotional intimacy.

Defying convention paid off with fans and critics. The 2017 film, according to White, was the best-selling of her career. “Angela 3” also scored six Adult Video News awards — the Oscars of porn — with White and Ferrara taking home “best boy/girl sex scene.”

XCritic.com porn reviewer James Sharp isn’t even a fan of “gonzo porn” — the storyless genre “Angela 3” fits within. He and his wife prefer the kind of plot-heavy epics that America’s best-known porn star, Stormy Daniels, directs. But White and Ferrara’s all-in performance stunned them.

“We both watched it and both of us had tears in our eyes,” he said. “It’s my favorite scene I’ve ever watched.”

Sharp added: “It was the most unique thing I’ve ever seen. I’m 50 years old and have been watching porn for over 30 years.”

Fans can only hope for “Angela 4.”

Industry forces are working against big-budget films like “Angela 3.” The increasingly far-flung porn business, coupled with the death of the old-school studio system, is making it hard for franchise films — even those starring two of the best-known names — to attract and maintain loyal followings.

White pulled off “Angela 3” because she’s one of the few industry veterans with enough clout to call the shots. She parlayed her on-screen success into her own production company, which gave her the freedom to write, cast, shoot and edit the film.

Few adult performers have her staying power. Most leave the business before anyone knows their name. Meanwhile, the never-ending supply of new 18-year-olds and the emergence of “webcam girls” offering custom porn has made it harder than ever for fresh faces to establish themselves.

Just a decade ago, the old-school porn studios signed the most popular entertainers to exclusive contracts and fans followed their favorite female stars by buying the studio’s big release. While those movies are still getting made, no one is waiting around for them to drop.

While “Angela 3” is a critical darling, it’s hard to gauge its commercial success. In keeping with the industry’s penchant for secrecy, White declined to provide sales figures. She would only reveal that DVD sales for the film were strong enough to cover the cost of production. “Angela 3” also ranked as the 15th-most-purchased DVD last year on Adult Empire, one of the largest online porn retailers in the world.

That might have been impressive before streaming smut and online piracy tanked DVD sales. Back in Jenna Jameson’s heyday, a top release might sell 100,000 copies. Now, a pirated version of Ferrara and White’s scene has garnered nearly 700,000 views on Pornhub.

The people who watch White on Pornhub are literally taking money out of her pocket. Like many big-name adult entertainers, White’s primary source of income is her website, where fans buy access for $29.95 per month. Customers get access to all the content White’s production company churns out, a library of her past work and access to her live shows. Roughly 70 percent of the money White makes off a movie like “Angela 3” comes from her site.

But firm numbers are hard to come by in the business — even more so since Pornhub entered the picture. MindGeek, the secretive company behind the Pornhub network, has hoovered up traditional porn studios, launched its own big brands like Brazzers and gained control of pirated-content websites. MindGeek has either bought or built its way into every corner of sleazedom since its launch in 2007.

The dominant porn site on the planet delivers kinks quickly and efficiently. Viewers can zero in on their specific sexual tastes, enjoy the best bits and move on. The average time spent on the site is less than 10 minutes — a far cry from White and Ferrera’s epic sex scene.

Most Pornhub users don’t have to pay for their viewing pleasure either, thanks to the nearly 6 million ad-supported videos on the site. For the consumer, the payoff is instant gratification and an endless stream of free smut curated to their precise tastes. The more viewers watch, the more Pornhub’s algorithm learns about them, and the more accurate its recommendations become.

While consumers love Pornhub, old-school producers are less than enamored of a newer model that is driving them out of business. Industry insiders say they are powerless to stop it, however, because Pornhub and parent MindGeek have infiltrated every corner of the business. A performer, for instance, might want her pirated scene to be taken off Pornhub, but if she complains too loudly, she risks retribution in the form of not getting booked for scenes being shot by Brazzers.

Meanwhile, the pay for adult performers hasn’t gone up in years. With porn moving away from the big screen and onto smartphones, anyone with an iPhone can get into the act. Fierce competition is keeping rates down.

For women hired by a traditional studio, the average pay is around $1,000 for a typical male/female sex scene. That rate goes up or down depending on the level of kink and the popularity of the performer. Men, on the other hand, make significantly less than their female counterparts, taking in around $500 for a single scene.

Superstars like White and Ferrara are the exceptions and can make double or triple the normal rate. A 21-year veteran with over 1,900 scenes under his belt, Ferrara says he basically sets his own rate to control how much he works. He’s made himself so expensive that he only works with the best studios, directors and co-stars.

White has starred in over 300 scenes and remains one of the most sought-after female performers in the porn industry. She also runs her own production company, AGW Entertainment, and is so well known in her homeland of Australia that she ran for office as a candidate for the Australian Sex Party in 2010.

White and Ferrara have performed together in over 20 scenes. Even so, “Angela 3” was special for them both.

“I didn’t think that arriving this late in my career I would be like, ‘By far, this is the best scene I’ve ever done,’” Ferrara told The Post. “This was real, pure, raw sexual perfect connection.”