If there’s anyone on the planet we trust to give us advice on how to get a bigger, curvier, perkier behind, it’s the guy who trains Kim Kardashian. In addition to working out the Kardashian family, Beverly Hills-based PT Gunnar Peterson also trained Jennifer Lopez, who you can objectively say is also the lucky owner of a pretty incredible, very-famous derriere, and is also the man behind other terrific ass owners, Ciara and Dakota Johnson.

When we asked, Peterson said that he would have to give the “best ass award” to his wife (cute), but admitted that his clients are also close contenders. He explained that when a woman wants to get a curvier butt, she’s usually referring to “enhancing the gluteus maximus and medius while keeping (or making) the waist small.” Specifically, women are wanting to create a “shelf at the top of the butt and distinct separation where the glutes meet the hamstring at the top of the back of the leg.” So think: Kylie Jenner in bodycon.

He also shared with us some recommendations of how you can get an ass of internet-breaking proportions all for yourself, without the fee of a celebrity-vetted trainer. Specifically, he makes his clients focus on lower-body exercises like “squats and lunge variations.” Next time you hit the gym, try doing 8 to 12 repetitions of squats and side lunges, followed by hip bridges. “I can’t recommend a weight because everyone is different. The weight should be whatever causes your form to fail between 8 to 12 reps,” he suggested. When it comes to doing the hip bridges, Peterson suggets using a weight plate, sand bag, or medicine ball on your bikini line as resistance. Or, try doing single leg bridges with no weights.

The biggest mistake women make when trying to build a bigger butt is simply giving up too soon, and not trying hard enough, so be sure to experiment with heavy weights: “The biggest mistake is that women aren’t lifting heavy enough in fear of getting big. They should push themselves!” Peterson advised. When it comes to the frequency with which you should hit the gym, that differs for everyone and will take some testing out to come to a perfect time frame: “Allow time in between heavier lifting days for your body to adequately recover,” he cautioned, adding, “This varies drastically between exercisers, so trial and error will be the best way to gauge.”

In addition to exercise, what you eat is important too—and also how much you eat. Peterson actually recommends eating more while you’re trying to get a curvier backside. “Consume quality calories above and beyond your normal caloric intake,” he said. “Start with 250 to 500 supplemental calories daily and make sure you’re happy with your progress.” After trying out the diet, if that feels like too much food, you can then pull back a little on the additional calories. “You need to eat adequate calories and get plenty of sleep, which is when your body recovers and builds muscle,” Peterson said.

And no, he’s not suggesting you inhale fries or Chipotle to get those extra calories: “Protein and carbs you need to eat right after your workout whether it be a protein shake with a fruit or chicken or fish with a sweet potato,” he explained. It’s also best to stick to whole foods rather than protein bars of protein shakes, however he concedes that these are OK “if you’re in a real bind” and pick ones with a high protein to low sugar ratio.