One fitness influencer wants you to know that social media is all about illusions—no ifs, ands, or butts.

Sia Cooper, who runs the popular Instagram account @diaryofafitmommyofficial, often shares side-by-side images of her body to denounce unrealistic  and point out how different angles can influence what a person looks like on camera.

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Last week, she posted brilliant insight into butt selfies—showing her followers how pulling up your underwear a certain way can totally change the .

“PSA: UNDERWEAR PLACEMENT MATTERS,” Cooper captioned a set of mirror selfies. “If you hike your undies up really high, it’ll give an illusion of a tinker waist and bigger bum. Just another popular trick amongst Instagram fitness models! So don’t be fooled.”

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🚫PSA: UNDERWEAR PLACEMENT MATTERS🚫 If you hike your undies up really high, it’ll give an illusion of a tinker waist and bigger bum. Just another popular trick amongst Instagram fitness models! So don’t be fooled 😉 Posture is also EVERYTHING. Be beautiful. Be you. Don’t fall into the trap of comparison. Work hard and trust the process. You’ll get there. 💜 PS: Having a 24/7 wedgie is not fun under any circumstances. @selfmagazine @shape @womenshealthmag @oxygenmagazine @people @fitnessmagazine @healthmagazine @muscleandfitnesshers @usweekly @theellenshow @cosmopolitan @elitedaily @scarymommy @redbook @glamourmag

A post shared by SIA (@diaryofafitmommyofficial) on Mar 20, 2018 at 8:16am PDT

This side-by-side was not a suggestion that her followers lift their undies up next time they take a belfie. In an honest disclosure, she provided an all-too-relatable postscript: “Having a 24/7 wedgie is not fun under any circumstances.”

Commenters praised Cooper for her transparency and thanked her for a much-needed reminder about the almost too-perfect body parts you see on your feed. A couple of days later, she illustrated her point by posting a photo of her “real booty” and then her “IG booty” with repositioned underwear.

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It’s amazing what a little bending forward, hiking up your underwear, arching your back, and sticking your booty out can do.. even whilst sitting down. Check out that waist, even! Butts typically don’t look great as you sit down (comfortably and normally). They flatten out and your cellulite tends to show because the skin is being pressed upon. However you see these chicks in bikinis who are sitting and it’s like magic or sorcery that their butts don’t flatten! They still look curvy and I’m like WTF.. I would get so upset because I knew I could not look like that all the time. But the truth is, nobody does. A picture is just a split second. We all look different from different angles. But all these angles are still our bodies. We are equally worthy in all our photos. @selfmagazine @shape @womenshealthmag @oxygenmagazine @people @fitnessmagazine @healthmagazine @muscleandfitnesshers @usweekly @theellenshow @cosmopolitan @elitedaily @scarymommy @redbook @glamourmag

A post shared by SIA (@diaryofafitmommyofficial) on Mar 22, 2018 at 7:46am PDT

“It’s amazing what a little bending forward, hiking up your underwear, arching your back, and sticking your booty out can do,” she wrote. “A picture is just a split second. We all look different from different angles.”