“Mom, Anna’s being mean!” my youngest daughter, Lilly, wailed, tattling on her older sister. Fights like this were once commonplace between the siblings in our family unit, occurring weekly if not daily. However, this particular fight just happened last week, and Lilly is 24 years old.

Lilly had called me from her own apartment where she lives as a working nursing student, after having a telephone argument with her 26-year-old sister, Anna, who is a fashion designer in New York City. The subject of their disagreement was rather innocuous, but the resulting verbal sparring cut them both to the quick and left them in tears.

It didn’t surprise me that Anna and Lilly still fight as adults, because I’m a sibling, too. And so is their dad.

My husband and I have learned that no matter how close we are with our siblings, the same old conflicts can break out well into adulthood. Maybe not over who called the other “Stupid-butt,” or who burped in church, or who ate the last Oreo, but adult sibling fights are still sibling fights nonetheless.

Sibling battles are more volatile than conflicts between friends, parents or coworkers. One minute, siblings are happily sharing a Tonka truck in the sandbox or a Barbie in the tub, and the next minute someone ends up with a scratched cornea. Arguably, this volatility springs from the natural competition ingrained in siblings from birth, as they scrape and claw for their parents’ attention and approval … and that last Oreo.

Furthermore, siblings generally experience all the ups and downs of their formative years side by side, exposing every emotion and fear to each other. Simple arguments can go from zero to 100 in a flash, because their vulnerabilities are just under the surface. Siblings know exactly how to push each other’s buttons.

When I was a squishy little kid, I had an older brother. When I wasn’t idolizing him (he was the smart, good-looking, athletic one), I was calling him a “big meanie” and telling on him to Mom and Dad.

Stories of our sibling battles abound, like the time he stole my baton and twirled it over my head while I whined and protested. The white rubber end of the baton flew off and broke a picture on the wall, but my brother somehow convinced me to take the blame. Like I said, he was the smart one.

Or the time he snuck up on me à la Cato from the original “Pink Panther” movies, and scared me so bad, I hit him with my hairbrush, bloodying his nose. Or the time he gave me the Hawaiian nickname “Lee Lae Lon,” which I hated, and led our entire school bus in a chant. “Gimme an L! Gimme an E! Gimme another E!” and so on, all the way to East Pike Elementary.

Once, while my cousin and I were playing house in our grandfather’s shed, my brother trapped us inside by standing on the roof and swinging a wagon down through the door every time we tried to get out, maniacally laughing as we screamed.

The conflicts between my brother and me continued, with a small respite during our teen years when we suddenly found Mom to be hilarious. My brother and I turned our attention to relentlessly mocking my poor mother’s quirks and mannerisms, and she didn’t protest because we were finally laughing instead of fighting.

As adults, my brother and I have laughed, but we’ve also had our disagreements. Each time, that thin veil that covers our vulnerabilities has been scratched open, leaving wounds that often take time to heal. But nowadays, I can’t run off crying to Mom the way I did when I was a kid.

“Are you gonna let Anna get away with being mean?” Lilly cried on the phone last week. As a 58-year-old mother of three grown adults, my instincts told me I was too old to get involved. Instead, I remembered an edict I once overheard my Kentucky aunt tell my squabbling adult cousins, “If you’re gonna stir up $#!t, don’t use me as a spoon.”

Calmly, I encouraged Anna and Lilly to work out their differences, and soon enough, they did.

Read more at themeatandpotatoesoflife.com and in Lisa’s book, “The Meat and Potatoes of Life: My True Lit Com.” Email: meatandpotatoesoflife@gmail.com