As the summer begins to bring more and more scantily clad women outdoors, now is as good a time as ever for men to see breasts. Step foot on any beach this season and you’re bound to catch sight of at least one perfect* pair, nestled freely in a woman’s bikini with nary a sweater or parka to shield them from the world. (Did we mention again how much we love summer?)

But we designate perfect with an asterisk because, let’s face it, we’ve all seen women with breasts that are a little too textbook. According to stats from the American Society of Plastic Surgeons, more than 290,000 women had breast augmentations in 2013 alone—meaning there are plenty of silicon-stuffed twins out there just waiting for guys to debate their authenticity. 

That’s where we come in. With the help of Norman Rowe, M.D., a renowned New York City plastic surgeon, we’ve put together a handy how-to guide that you can use to tell if a woman’s breasts are bogus just by looking at them. 

1. 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. 

2. 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. 

3. 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.

4. 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. 

5. You Can Hear Sloshing

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.