Molly Sims Kid-Proofs Her Furniture with Outdoor Fabrics: 'There's a Child Vomiting at All Times!'

As a mother of three, Molly Sims has learned the tricks of the trade when it comes to shielding against messes.

The author of Everyday Chic: My Secrets for Entertaining, Organizing, and Decorating at Home — Sims’ second book — reveals to PEOPLE in this week’s issue that she has a unique way of preserving her furniture.

“There really is outdoor fabric on all my indoor sofas and cushions because I’ve got to tell you, there’s a smoothie, there’s formula, there’s a dog, there’s a child vomiting at all times,” explains Sims, 44, who is mom to Grey Douglas, 9 months, Scarlett May, 2½, and Brooks Alan, 5.

“I’m a little OCD because of having so many kids in such a short amount of time, and living out of suitcases for 15 to 17 years makes you neat.”

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RELATED VIDEO: Molly Sims Reveals How Her Daughter’s Tendencies Are “Payback” for Her Childhood

Sims admits having three children is “hard,” drawing comparisons between her current life and experience parenting just one child.

“One is like a pocketbook — it’s like a great accessory that you cherish and love and you can put it down,” she says. “Two play with each other, three … it’s like yesterday he was in his little car and somehow he sauntered out of the car onto the floor. That’s what this is about.”

“It’s embracing the happy mess,” she adds jokingly. “I love them more than anything. I think I French-kissed Grey the other day, I love him so much. [I think], ‘When everybody is gone, I seriously wish there’s just going to be me and you. You’re all I need.’ ”

Sims’ newest project is Everyday Chic, which she says she worked on for two years. (Her first book — The Everyday Supermodel: My Beauty, Fashion, and Wellness Secrets Made Simple — was released in 2015).

“I was driving myself crazy, I had to finish it,” she admits. “I had such a hard time with the title — like, ‘That doesn’t represent me, it can’t be called that.’ ”

“But I always say that I love things that are chic, I’ve never met a couch I didn’t like,” Sims continues. “I love a good product that is packaged well.”

“The first book focused on how to be the best you can be inside and out,” Sims explains. “Now three years later, two babies more, the book is a reflection of how [to] live the best life you can, and how [to] live it with style and gratefulness and being a little bit chic and getting it all done with grace.”

Everyday Chic: My Secrets for Entertaining, Organizing, and Decorating at Home is available for purchase now.

For a closer look inside Molly Sims’ family of five and her new book, pick up the latest issue of PEOPLE, on newsstands now.