She’s helping her clients get a room.

Melanie Rose is the unflappable host of the new Netflix reality series “How To Build a Sex Room” out Friday, July 8. Each episode follows the deceptively prim and proper British interior designer as she meets with various couples who describe their fantasies and ask her to transform a space in their home into a private carnal paradise. 

“Darling, I’m the Mary Poppins of sex rooms,” Rose, 57, told The Post, referring to her randy bag of tricks.

One of her clients, she said, gave her that nickname, which suits her. “I’m very English, upper class, as it were. Very classy … don’t dress like a dominatrix.”

And yet she’s helping people transform their homes into kinky playgrounds. For polyamorous couple Lester and Soriya, that included creating a “luxury dungeon” with a 9-footwide bed to accommodate the couple’s five partners, not to mention a closet with baskets containing each lover’s favorite sex toys. There are also restraints paired with sensual velvet panels and a tasteful piece of furniture that doubles as a cage.

Burlesque performers Bettie and Brody, meanwhile, wanted a room to connect in while transforming into their nighttime personas. And so Rose designed them a bathroom with a Hollywood glam feel — complete with a soaking tub for two and feminine details blended with bondage elements, including a suspension bar hanging from the ceiling for the couple to explore the form of Japanese rope bondage known as shibari.

A Surrey, England-born, Los Angeles interior designer who originally specialized in luxury kitchens and bathrooms, Rose got into the world of sex rooms about a decade ago, she said, when a client asked if she’d ever designed one. 

“I said, ‘No,’ but I was curious. So, I went home and did some research and looked at various dungeons. I thought, ‘Oh my goodness, those don’t look very appealing, I’m sure I could do better!’

“That’s when I started designing sacred rooms, fantasy rooms,” she said.

On the show, Rose visits each couple at home and assesses the space that they want to turn into their sex room, such as a basement or a spare room.  

“As soon as you mention sex room, the image that some people create in their mind is something disgusting and dirty. And it’s not,” she said. “I’m bringing couples together, I’m creating a conversation with partners and bringing them what they desire in their fantasies.”

After she discusses the logistics of the space and the couple’s vision for it, Rose then discusses their various kinks and bedroom habits. The key to a good sex room? Her Mary Poppins bag of tricks, which includes sex toys such as handcuffs and floggers.

“It’s a tool of the trade that I’ve picked up and progressed with,” Rose said. “If I was sitting next to you, I would bring out my toys and gauge your reaction. If I bring out a butt plug, some people are like, ‘Oh, whoa, that’s a hard no.’ Handcuffs deliver a reaction. A flogger delivers a reaction. My job is to find out what they are looking to bring into that room to further spice up their sex life.”

One couple on the show, Taylor and Ajay, express an interest in exploring bondage.

Rose outfits their sex room with a St. Andrew’s (or X-frame) cross, restraints on a bed and various other naughty props. Rose then arranges them on shelves or along the walls, considering mood lighting, carpeting and soft lounge furniture tailored to each couple’s style preferences.

She declined to answer whether she’s designed sex rooms for celebs — “because I signed NDAs” — but Rose said that she’s never been presented with a kink that stumped her.

“I haven’t had one before, but I’m open to everything. And also if I’m not familiar with it —and I’m familiar with most things — I would do the research myself,” she said.

For Rose, the biggest rule of sex rooms is that there are no rules: “Sex rooms aren’t for one type of person. They’re for everyone.”