What does it take to make Gwyneth Paltrow blush? Not much more, it turns out, than some explicit coaching on how to tone her pelvic floor. Her instructor, Betty Dodson, the fine artist turned sex educator and evangelist for female self-stimulation, was preaching the benefits of the Kegel-like exercise that Ms. Dodson maintains can help trigger an orgasm.

“Lift up, squeeze, release,” she coaxed, prompting Ms. Paltrow, purveyor of a $75 candle called This Smells Like My Vagina, to turn pink from her jawline to her brow.

That scene, from “The Goop Lab,” on Netflix, a look at Ms. Paltrow’s millennial-friendly lifestyle business, was a milestone for Ms. Dodson: rendering her more visible, and arguably more relevant, than she has been since she began teaching women how to climax a half century ago.

“There are younger educators now,” said Annie Sprinkle, the 1970s pornography star turned sex educator and longtime Dodson disciple, “but Betty can still rile them up.”

A disrupter before that was a buzzword, Ms. Dodson has consistently proselytized her sex-positive ideals over the decades, urging participants in the Bodysex workshops she founded in the ’70s to sit in the buff on her carpeted floor, peer at each other’s vulvas and learn to masturbate effectively.

Even before the New York City health department advised “you are your safest sex partner” in a widely circulated memo, Ms. Dodson, now 90, was enjoying a timely rebirth. Her message resonates in the 2017 primer she wrote with Carlin Ross, “Bodysex Basics,” and in a reissued version of her 2010 memoir, “Sex by Design: The Betty Dodson Story”; in the popular workshops she holds every month in her Midtown Manhattan apartment (now on hiatus, replaced by group chats online); in the erotic art that first gained her attention, her images of copulating partners to be exhibited late this year at the Museum of Sex (if and when it reopens), to which she is an adviser; and on dodsonandross.com, the website she maintains with Ms. Ross, her 46-year-old business partner and heir apparent.

On “The Goop Lab,” Ms. Ross lies prone in a darkened room. Ms. Dodson is poised over her, helping to smooth oil into her genitals, demonstrating a hand-over-hand massage technique, and murmuring gently as she guides Ms. Ross toward an eventual climax.

If the earth moved for Ms. Ross, it wasn’t apparent. Apart from some accelerated breathing and gentle quaking, her experience looked and sounded nothing like the auditory and visual fireworks that have long been a mainstay of heterosexual pornography.

If it seemed tame by comparison, Ms. Ross said, “that’s because it wasn’t a performed orgasm.”

She was chatting before the spread of the novel coronavirus sent New Yorkers into self-isolation, in the combined office and bedroom where she and Ms. Dodson write and plan their projects.

A gilded, winged penis, one of Ms. Dodson’s oddly assorted awards, claimed pride of place on a high shelf of a bookcase otherwise lined with self-published videocassettes like “Viva la Vulva,” and germinal works including “Sex for One: The Joy of Self-Loving,” her groundbreaking 1987 primer on female masturbation.

Ms. Dodson made her entrance dressed in a slouchy bathrobe, its chest pocket monogrammed with the letters, B.A.D., “my initials, Betty Anne Dodson,” she said, eyes crinkling, before returning to her theme.

Sure, an orgasm can be noisy at times. “Usually, though, the sounds are a lot more guttural, deeper, more animalistic,” she said. “The legs tremble, the whole body trembles. I’ve never seen that in pornography.”

So why do so many women feel obliged to put on a show enhanced by a soundtrack of moans and shattering screams? “The guys don’t want to see real orgasms, they want the porn orgasm,” Ms. Dodson said caustically. “It’s an ego thing. They want to see the kind of effect they’re having on a woman.”

“A real orgasm,” she added, leaning forward for emphasis, “is something that no matter where it comes from, a woman takes for herself.”

It’s a precept central to her teaching. “You’ve got to run” intercourse, she enjoins of women: Take charge, that is, become an active participant in your own pleasure. If you are with a partner, “Get ’em to do what you want,” she all but barked. “Get the position you want.”

Manual or battery-powered, masturbation is, in her view, the cornerstone of sexual fulfillment, a catalyst for pleasure, and, more than that, the reliable foundation of social and emotional independence.

“Instinct told me,” she writes in her memoir, “that sexual mobility was the same as social mobility. Men had it and women didn’t.”

Her take-charge attitude, subversive, even incendiary in the early ’70s, did not sit well with some feminists, who deemed Ms. Dodson’s notion of coupling mechanical and lacking in connection. They were, moreover, far too intent on calling out the abuses and indignities endured at the hands of men. “They were always complaining,” she recalled testily.

Undaunted, she responded with a form of sexual consciousness raising; vital to her message was a full-on repudiation of romantic love. “Romance is so serious,” she said in her apartment. “It’s no longer that paradigm, where I have to love you and you have to love me back.”

Ms. Ross chimed in: “Sex can be playful, more like, ‘Let’s have some fun.’”

Ms. Dodson’s epiphany arrived in the wake of a rocky, sexually tepid marriage in the early 1960s to an advertising executive, Frederick Stern. The couple had no children, nor did Ms. Dodson, who grew up with three siblings, plan on having them in the future. “I watched what my mother went through,” she said. “It’s the most thankless job on the planet.”

Free to experiment, she explored group sex with women and men, her objective, she said in a 1970 New York Times interview, to let go of jealousy and possessive feelings, “to understand I could love more than one person.”

She eventually became disenchanted. “Organized group sex is a little bowling-league kind of thing,” she said at the time. “It’s super‐compulsive — there’s a frantic quality to it. It’s weird.”

With a small settlement from her divorce, she financed the first of the sex workshops for women that were to become her livelihood and calling. At them, she urged often skittish participants to strip down, discover their bodies and embrace practices involving clitoral massage and the use of the Magic Wand, the slightly unwieldy but highly efficient vibrator she promotes and sells through her website, Dodson and Ross.

Her closely shorn white hair and sagelike demeanor invites comparisons with Dr. Ruth Westheimer, the cozily entertaining sex guru who mainstreamed in the 1980s. Ms. Dodson isn’t having it. “Dr. Ruth is your grandmother with a funny accent,” she likes to say. “You never listen to what she says.”

The comparison is apt — to a point, Ms. Sprinkle said. “Dr. Ruth is safe, whereas Betty is edgy, a progressive explorer of sexuality. She has the kinds of experiences that even her younger followers will never have.”

A performer to her core, Ms. Dodson has cultivated a persona that swings between gruffly abrasive and genial, and she can be wryly funny at times. Since being given a clean bill of health by her doctor last month, after a routine checkup, she has taken up smoking for the first time in years.

“Why not?” she said with a hoot, “I’m going to live forever.” But when Ms. Ross suggested that she was free to light up any time, she bristled. “I’ll decide when I smoke.”

Groundbreaking in their day, Ms. Dodson’s teachings will hardly startle young women, growing up as they did watching pop idols like Miley Cyrus, Nicki Minaj and others stroking themselves in videos and on the concert stage.

Their lyrics, too, make self-stimulation sound as routine as a trip to the mall. “Oh what an ordinary day,” Annie Clark, known professionally as St. Vincent, croons on “Birth in Reverse,” her 2014 single, “Take out the garbage, masturbate. …”

A younger generation has ready access to online guides like “How to Masturbate, Female Style: 8 Steps to Having Orgasms,” on Bustle, the instructions handy, as the author writes, “because knowing several ways to get yourself off is something everybody should have in their skill set.”

A similar matter-of-factness underpins a somewhat glib assertion by Flo Perry, a 27-year-old British writer and illustrator, in “How to Have Feminist Sex: A Fairly Graphic Guide.” Masturbation can function as nothing much more than “a form of self-care,” she writes.

Still, some younger women seem to prefer Ms. Dodson’s hands-on (if you’ll forgive) approach. The classes that she lists online are crowded with clients, roughly half of whom range in age from 24 to 40, according to Ms. Ross. A few may respond to the current of rage that runs through Ms. Dodson’s writings and heats up her conversation.

She recalls in her memoir an instance in which an older friend makes groping advances on her best friend. Snatching a blade from a nearby cutting board, she hisses, “You better get out of here before I shove this knife into your stomach.”

Yet, in other instances, Ms. Dodson seems unaccountably cooperative. Deep into her memoir she describes a back yard encounter with a demi-clad stranger, who was hovering menacingly at her back. Sensing that he was about to pounce, she pivoted, undid his belt, pushed him into a chair and mounted him.

It’s a startling incident to read about, all the more so in the #MeToo era, when Ms. Dodson’s seemingly cavalier attitude has the ring of heresy. But she isn’t about to recant. “Unless you are a martial artist,” she said, resisting a man during an attack “is mostly useless. Men are bigger and stronger. I don’t care what your motives are — fighting doesn’t work.”

Her relationship to the burlier sex can be tartly dismissive. “Men are so two-dimensional,” she said. “If there is anything interesting about them, it’s because of the women they’ve been with.”

Ms. Ross reminded Ms. Dodson that in her mid-70s, she had a 25-year-old lover with whom she lived for a decade. For Ms. Dodson, the memory still sets off sparks.

“He was so beautiful,” she said between wistful puffs on a Marlboro Light. “He had the perfect body, broad shoulders, good-size genitals and tight bones. And oh, he smelled so good — that youth, and a lot of soap and water.”

“Partner sex, that’s over now,” she went on. “But I wouldn’t turn down a good-looking guy if he walked in now.”

Being without a partner is no reason to abandon the field, she added matter-of-factly, confiding that she still smokes marijuana on occasion (“I wouldn’t be here without it.”), sometimes as a prelude to occasional solitary sex.

No point sitting back, hoping idly to be overtaken by desire.

“We get desire once we are aroused,” she said. “Don’t wait for the spirit to move you, because it never will.”