Poised on a chair before a group of American students, who are hanging off her every word, Myka Meier leans forward and lets them into a secret.
The magic, she explains conspiratorially, comes from the knees and ankles.
As the 30 students take notes, watching intently, Mrs Meier reveals the essence of "The Duchess Slant" – a seating style she deems the epitome of elegance.
To achieve posture worthy of the Duchesses of Cambridge or Sussex – Meghan Markle, one of their own, of course – knees and ankles must be kept together, with the lower legs elegantly tilted to one side.
Think "Princess Diana at the Taj Mahal," she urges. "You might think you'll never get that invitation to the palace," she says. "But you never know."
America is in the grip of Meghan Mania. Since the Los Angeles-born actress married Prince Harry in May, etiquette teachers across the US have confirmed a surge in interest in their classes.
"Markle Mania is alive and well on the West Coast," said Elaine Swann, who founded The Swann School of Protocol, in San Diego in 2003. "In California we're known to be more casual. But people here are fascinated.
"If I post anything related to Meghan on social media, it gets serious traction. Individuals are contacting me about classes. Girls want tea parties, and women want to look more polished. It's certainly happening, and it's exciting."
Next month Mrs Swann will hold a special series for women, answering questions on "refining and redesigning your look" with the Duchess of Sussex as the inspiration.
"She's got a great balance between respecting Royal protocol, and remaining true to her roots," says Mrs Swann. "I'm very proud of her. She's developing into a fine role model."
The Duchess was the most-searched person this year around the world, according to Google – and the second most in the US, behind Demi Lovato and above Brett Kavanaugh.
In her homeland, interest was highest in Washington DC, Maryland and New York City, peaking around the time of the wedding, but remaining strong ever since.
"'Markle Sparkle' Is the new 'Rihanna Effect'", announced Vogue magazine's US website, decreeing that a new fashion icon – with the power to sell out clothes in minutes - had been found.
"It was widely assumed that Meghan-mania would die down and things would soon return to normal," wrote Tom Sykes in The Daily Beast. "That very definitely has not happened."
Brides magazine, furthermore, suggested: "Embrace the Markle Mania this holiday season with these Meghan Markle-approved holiday gift ideas."
"We've definitely seen an uptick of interest," says Crystal L. Bailey, who founded The Etiquette Institute of Washington seven years ago.
"A number of finishing schools are now opening up. And it's not just young people – it's adults, too. Every time I speak, I'm now asked about Meghan."
Terri Thompson, a Kentucky-based Etiquette In Action consultant who teaches classes all over the US east coast, agrees. "I think the resurgence of the Royal family in the UK has certainly caught US interest," she says. "We were always intrigued. But now, with Meghan, we are definitely more so."
Mrs Meiers, who was trained by Alexandra Messervy, a former member of the Queen's household, and by former BBC newsreader Diana Mather, launched specialised training in Royal manners in 2013.
Her day-long course, The Duchess Effect, is held several times a year in New York, and always sells out – the most recent one saw two participants fly in from Brazil, three from Canada and one from Australia for the $1012 training.
"It was sparked from my own personal interest," said the Florida-born businesswoman. "Could just anyone actually become regally polished through training?
"We saw Kate Middleton do it, but she already had the British background and education, and was very polished to begin with. And so my experiment became myself really."
Bearing more than a passing resemblance to the Duchess of Sussex herself, Mrs Meiers had her students' rapt attention, seated in rows in the ornately wood panelled Edwardian Room of The Plaza hotel.
A stylist from Texas was fascinated by the demonstration of how to juggle canape, clutch bag and cocktail.
A family of four from North Carolina – mother, father and two daughters – took notes as she demonstrated the correct way to hold cutlery.
In the front row a 50-something businessman listened intently as she discussed the value of pocket squares and shiny shoes – noting, with a photo of Prince William in her powerpoint, how he sat with the soles of his feet pointing down.
Another photo showed how he walked slightly ahead of the Duchess of Cambridge as they descended the stairs – giving her gown space to flow, but ready to catch her if she fell.
"An American Duchess"
"Having an American as a Duchess has captured everyone's imagination," said Serena Jones, 20, a biomolecular science student at New York University.
"My mum really wanted to come to this class with me!" A student from Maine nodded. Her friends, many of whom worked in tech, had laughed when she told them how she planned to spend the weekend.
But she was unabashed – taking the course, she felt, would give her the edge in a competitive work environment. Catherine Britton and her husband Russ had travelled from North Carolina with their daughters Caroline, 22, and 20-year-old Elizabeth.
"We live on a beach, which is really relaxed, so I wanted to learn more about how things should be done," said Caroline. "I've just started a job with KPMG so I wanted to get some tips, to feel comfortable at work dinners and parties, and better able to express myself."
And all agreed that Ms Markle served as an inspiration. Michael Carne, a businessman from Dallas, attended with his fiancée, Roxanne, a stylist.
"We're big fans of Meghan's," said Mr Carne. "The course was so helpful – I thought the dining class was great, and I learnt a lot about styling. I'm going to go home and find myself a good tailor."
Mrs Meier was thrilled by the surge in interest. A documentary series is in the works, she has launched her own clothing range, and her 40,000 Instagram followers are treated to sponsored guides to Boodles Gin, features on Hermes scarves, and tidbits from her forthcoming book.
"Meghan Markle's entrance into the family as the new Duchess of Sussex reinforces that you don't have to be born into a certain bloodline, from a certain race or raised in a certain place to learn the skills to become the best, most polished version of oneself," said Mrs Meier.
"As a British-American, I really am proud of the Duchess of Sussex - from both sides of the pond - and think she is doing an excellent job.
"She shows people that anything is possible, even if society tells you otherwise. She's leads the dreamer revolution to an entirely new level, in a truly positive way."