On a recent weekday afternoon in a SoHo loft, smiling partygoers crowded around a three-layer vanilla birthday cake covered with rainbow frosting, sprinkles and cherries.

Performer Lindsay Dye entered the room. She eyed the crowd, approached the cake — then plunked her bare butt smack on top of it.

Over the next 15 minutes, the raven-haired vamp sensually smeared globs of Pillsbury frosting and cake crumbs all over her back, thighs and buns.

The fetish, known as “cake sitting,” is how Dye makes ends meet.

“I never in my wildest dreams thought I could actually make a living doing this,” the 29-year-old Brooklynite told The Post. “But here I am, and I couldn’t be happier.”

Dye typically does three shows every week, raking in $150 per 15-minute session. She charges $50 for each additional half hour. The performer also offers homemade cakes for $50, or $25 for a custom cake design.

But audiences definitely can’t have Dye’s cake and eat it, too.

I’ve had people go face first into my butt, and that’s not something I’m cool with at all.

“They can look, but can’t touch,” she stated firmly. Still, the policy — announced before her act every time she performs — hasn’t stopped some from trying.

“I’ve had people go face first into my butt, and that’s not something I’m cool with at all,” said Dye.

The cakes aren’t the only tantalizing treats on display — Dye’s get-up is all about showing off her goodies.

Before every performance, she slips on a see-through bodysuit, black knee-high stockings, six-inch acrylic stripper heels and a waist-length hairpiece. She also puts on knee pads.

“If I don’t wear the pads, my knees get destroyed from all the sitting and dancing,” said Dye, who began performing the X-rated act throughout New York City two years ago.

The Miami native has nearly 150 crushed cakes under her garter belt. She’s performed at events ranging from corporate parties (music app Treble and porn magazine Math are past clients) to sexual bondage gatherings.

Clients book the curvy seductress through her website or Instagram page, which has nearly 12,000 followers.

Dye’s clients have included the proud father of a boy turning 18 — the host of the recent SoHo party.

“I’m looking to book a performer unlike anything else these kids have seen before,” the dad explained in an email to Dye.

“I just thought, ‘Wow, these parents must be really cool,’” she said. “Usually people hire singers and bands for their kid, not a cake sitter.”

Dye wore her signature look to the loft, where the birthday boy’s parents had set up a bed and lighting and brought extra cakes for the show.

She draped a clear tarp over the bed (as she always does, for easy clean-up) and squatted down into her opening pose with her knees spread on the ground and butt resting on her heels.

Finally, Dye began “teasing” the cake with her backside as a mix of SoundCloud rappers blared over the speakers.

“There’s always some point in the music, maybe a crescendo, when I finally start sitting,” she said. “I sit and sit over again, but after four to five sits, I put my hands in it and wipe it.”

Dye — who also works as a webcam model performing sexy acts for clients online — found her cake calling after a man cruelly asked her to crush her own cat.

“Obviously, I wasn’t going to do that,” she said. “But I started researching crushing fetishes that were more pure and wholesome and found this.”

The innocence of cake, and its association with children’s birthday parties, are what make the fetish so popular, Dye said.

“I’m taking something that’s pure and wholesome and defiling and sexualizing it,” she said. It’s “hot, funny and disturbing all at the same time.”