Adapting a worldwide phenomenon like Fifty Shades of Grey into a film can be a huge risk. There are millions of fans to appease, an author’s own vision to consider, and a taboo subject to navigate for the masses.

But for director Sam Taylor-Johnson, all of those risks motivated her.

“I knew it was going to be an enormous challenge,” Taylor-Johnson told The Daily Beast. It’s only her second feature film—her first being 2008’s Nowhere Boy, which chronicled the early life of John Lennon—and the subject was relatively unfamiliar territory for her. “But that’s partly why I did it.”

When we met at the Mandarin Oriental in New York City, the 47-year-old mother-of-four had already endured days of screenings and non-stop interviews. She felt exhausted and was ready to get home to her family. Yet the British native looked perfectly refreshed and poised while sipping tea and admiring expansive views of the city and Central Park.

I was there to talk about sex—something that has always come easy for the formally trained artist. It’s been an integral part of her life and work, extending far past her days painting nudes at Goldsmith University in London and seeping into many of her post-grad works, like the short film Love You More which revolves around two teenagers navigating the loss of their virginity. She also made an hour-plus long video of David Beckham sleeping, which became a much-talked-about art event in 2004.

“It’s what makes the world go round and what keeps us in existence,” Taylor-Johnson says of sex. “The human race relies on us to keep having sex. It’s part of who we are.”

And while sex may no longer be taboo to general audiences, the particular sort in 50 Shades of Grey can be to the masses. BDSM (Bondage, Discipline, Sadism, Masochism) is often misunderstood and misrepresented, seen as a violent and demeaning practice.

So no matter how much research you do and knowledge you have, it can be hard to translate the physically demanding world of BDSM to a wide-ranging audience in a romanticized capacity.

“I didn’t want to go into this movie naïve and not understand that world,” Taylor-Johnson said of exploring BDSM culture for the film. “It wasn’t really my interest to go too deep into the really heavy stuff because this had to remain a romantic and intense love story.”

Taylor-Johnson spoke to “various different people”, and “from what pretty much everyone said across the board was how powerful the trust had to be in order for whatever fantasies and desires there are to be fleshed out. There is a very binding contract. How often do you go into a relationship where you go ‘OK, sign what you will and what you can and can’t and what you’re willing to do.’ I thought it was quite interesting to understand what comes of that trust, and such a powerful and unique love.”

The scenes caught on film show a lot of skin and a lot of sex, but shies away from anything overly explicit. The BDSM is light, but Taylor-Johnson manages to capture the right elements of the kink dynamic to “understand the world that they were in without taking you into a place of further darkness.”

Taylor-Johnson’s first and only prior involvement with BDSM culture was in 2004. Taylor-Johnson, who is also a trained photographer, wanted to do a self-portrait floating in mid-air. So, she hired a man, Master RopeKnot, to tie her up bondage style and suspend her from the ceiling. It was a limited experience, but it was a start.

“The thing that I really wanted to take from everything I learned was how powerful the trust had to be,” she added. “People tend to go straight into the world of pain and all of that, but it’s not just about that.”

The trust extended far beyond the research, into the daily lives of the cast and crew. Taylor-Johnson and her cinematographer, Seamus McGarvey, carefully navigated the filming of sex scenes. “I knew when we got to that point they would all be sensitive minded people,” she said. “The atmosphere was very hushed, very respectful, and felt like another day.”

The most intense sex scenes were saved for the later days of filming in order to build up enough trust and respect with the cast and crew. A lot of music was played to keep the mood light.

“It stops everything from being really hushed and every so often I would put something on just to make them laugh.”

Which would often be needed to break up the repetition of some of the novels most intense sex scenes. “It was tough. There were days where we had to take long breaks and recompose,” the director said. “They are human beings and the nature of this was difficult. Both [Dakota and Jamie] needed their own time to take a break. It was intense.”

For Taylor-Johnson, “it was difficult from the offset of understanding that this was a phenomenon and this had a hell of a lot of fans that really wanted me to pull this off and make it right.”

That pressure was combined with the presence of author E.L. James on set, who Taylor-Johnson clashed with. “Working with such a beloved book and such an involved author” was tough, says Taylor-Johnson. “Sometimes you have to collaborate and be open too, and sometimes you just have to go head-to-head.”

Taylor-Johnson told NBC’s Today that the conflict was between “two very visual people” over what should appear on the screen.

Due to the first film’s early success—it is the fastest pre-selling R-rated ticket in Fandango history and projected to bring in $60 million more than projected—news of two follow up films, Fifty Shades Darker and Fifty Shades Freed, have already been announced.

The sexed-up franchise will continue, though it’s unconfirmed who will be involved, although Taylor-Johnson told NBC’s Today she was “on board” for film number two.

Right now though, Taylor-Johnson just wants to be at home with her kids.