They’re Too Close to Each Other: Most women’s breasts have 2 to 3 inches of space in between them, but implants shrink that gap significantly. If it looks like hers are touching in the middle, they’re likely fake. “When doctors put in implants, most of the time they’ll just pop them in and set the breasts very close to each other, near the midline of the chest,” says Dr. Rowe.

They’re Too High Up: Another dead giveaway: her breasts are set too high on her chest. Usually, they should sit right around where the armpits are, but a botched boob job when implants are placed in from the armpits can make the breasts ride up higher, Dr. Rowe says. This is easier to see when women are wearing swimsuits, because padded pushup bras also lift up breasts.

They Look Like Cantaloupes: “Natural breasts are shaped like pears or teardrops, but if hers look more like big, round melons, that’s a telltale sign they’re fake,” says Dr. Rowe. That’s because unlike real breasts, which are naturally fuller on the bottom, implants are evenly distributed with silicon or saline from top to bottom, creating a perfectly round shape.

You Can Spot Scars: Plastic surgeons generally use four access points on the body to put in implants, all of which leave scars: The belly button (look for a scar about half an inch up from it, toward the abdomen); the inframammary crease between the breasts and chest (leaving two symmetrical scars at the bottom of the breasts); around the nipples (but she’d have to be topless for you to see it); and the armpits, which leave the most noticeable scars. “If a woman’s wearing a tank top and she lifts her arms up, look for 2-inch scars under her armpits on either side,” says Dr. Rowe. And unlike the belly button, which could be an incision point for other surgeries like appendectomies, not too many other surgeons use the armpit for other procedures, he says.

You Can Hear Sloshing: If you put your ear to her chest and it sounds like you're at the beach you might be dealing with fake boobs. But no seriously you might need bionic ears (or just a quiet room) for this one to work, but here’s a sign you can actually hear instead of seeing: Women with saline implants—an alternative to silicon—will sometimes give off a “sloshing” sound when they move side to side. That’s probably the result of the surgeon filling up the implant once it was inside the woman’s breast. “If the implant doesn’t fill up all the way with saline, it creates an air pocket, which is audible. It’s not something you’d notice on a woman walking down the street, but you can definitely hear it in an intimate setting,” Dr. Rowe says. So listen up.