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photos of children

A child gives an awkward smile.

Taking photos of your child can be frustrating. They need to do everything that kids don’t like to do: sit still, pay attention and look directly at the camera. It’s also tough to get a natural smile. When many kids take photos, they twist their faces into a grimace like Matthew Perry on “Friends.”

That’s why nearly 300,000 people liked a Tweet from children’s author Adam Perry. He shared side-by-side photos of his 5-year-old son to show how his smile improved dramatically after he said the magic word—and it isn’t cheese.

“My son when I tell him to smile vs when I yell out ‘poop!’” Perry wrote on Twitter.

Perry is the author of The “Thieving Collectors of Fine Children's Books,” “The Magicians of Elephant County” and “The Big Book of Horrendous Diseases.”

The writer explained the origin of his fantastic discovery to Good Morning America. “We always take pictures on the first day [of school] and we were in a bit of a hurry and having a hard time getting good pictures," Perry said. “My son always has the funniest smile when he’s trying too hard. I learned at some point that if I just yelled out ‘POOP’ and snapped the picture quick, it always worked out way better. In this case, it was a pretty dramatic comparison, so I thought I’d share it.”

Perry couldn’t believe how quickly the tweet took off.

"I expected 5 to 10 people to like it. Then it kept climbing...and climbing...it's now at 297k likes. Then it went first page on Reddit and viral on Instagram and Facebook," Perry told Good Morning America.

The tweet inspired countless parents to share their magic words to get their kids to smile in photos.

"Our family phrase for smiling in pics isn’t 'cheese'; it’s 'cat butt,'" John Horton wrote.

"My kid likes me to say 'fart, poop, dootie' - bc it is the 'curse' word stream in Boss Baby and it makes her laugh," Marie replied.

USAF Lady Vet 410 FMS shared some wisdom for the ages in the thread: Never tell a child to smile.

"I was a school photographer for years. Elementary age kids were great. Chicken lips, stinky feet & turkey toes would produce the most natural smiles. Never tell a little kid to ‘smile’ if you want a natural expression. Beautiful pic by the way!" she added.

Perry is over the moon that his tip has helped parents with a problem that so many face. "They're like, I tried it and it worked!'" Perry told Today.com. "Also, it doesn't just work with kids. Adults are doing it too to make each other laugh in pictures."

Perry’s son was also excited to have his moment in the sun.

“He is very excited to be in his words—famous—" Perry shared. “He had a little article and his picture in the local paper. He’s having his 15 minutes a little early and thinks it’s all very cool.”