After eating a trough of Thanksgiving chow and assorted goodies, I head to the mall to find the perfect little black dress to wear to Spouser’s office Christmas party. Just for fun, my friend Myrtle comes along.

“Besides the brassiere, you look like a freshly plucked chicken,” she says, poking her head inside the curtain of my dressing room.

“Thank you very much,” I reply, waving for her to move on and try on the leotard thingy she’s holding.

Then I slip out of the dressing room wearing one of seven dresses I’ve tried on, the only dress I’m actually able to zip up without turning blue. Taking a slow turn at the four-way mirror, I’m suddenly eclipsed from what I think is the sun. It’s Myrtle who has appeared fresh from her dressing room wearing a bright yellow outfit that makes her look like Oprah squeezed into a Kill Bill jumpsuit.

The people standing around become quiet and stare, when suddenly Myrtle opens her eyes to the size of a satellite dish and lets out a bloodcurdling scream. At first I’m not sure if she’s screaming at me, or if she’s zipped up her skin in the zipper.

Head stretched back over her shoulder, Myrtle spins around and around like a dog chasing its tail, then collapses on the floor in a heap. Her plump golden legs sprawled out in front of her, she gazes straight ahead in a glassy-eyed stupor.

“Get back! Make way!” I say, pushing aside the gawking women with price tags hanging all over them.

The path cleared, the department store manager rushes to Myrtle’s side.

“Are you a doctor?” a woman with a Miracle Bra fastened around the outside of her T-shirt asks.

“No,” the manager says, “but I’m married to one.”

Awestruck, a murmur filters through the crowd. I am wondering if a turkey bone has made its way through her digestive system and lodged itself in an uncomfortable spot, exacerbated by the lack of stretch in the jumpsuit.

The manager takes Myrtle’s hand and pats it. “Miss, Miss, talk to us, Miss,” she says.

When Myrtle’s lips finally start to move, the manager leans down and puts her ear up to Myrtle’s mouth. She listens for a minute, takes a deep breath, and then stands up.

“I thought so,” the manager says solemnly. “I’ve seen this hundreds of times. It’s a severe case of sinking gluteus maximus.

“Butt drop?” I ask to be sure I understand.

Gasping, the crowd shrinks back in horror. I turn around to check my own derriere’s position. Instinctively, every woman in the place does 10 quick tushy tucks.

“For glutes’ sake, it’s not contagious!” the manager snaps and props Myrtle up against the mirror. “It’s more of a genetic thing, but when it hits, it’s always a blow, like a helium balloon deflated.”

“How bad is it compared to others you’ve seen?” I ask quietly. “What can I do to help?”

“It looks critical,” the manager replies, which is the medical term for submarines can’t sink this low. “She’ll need a lot of love and encouragement.”

On the way back home, my not-so-little black dress, in its clear plastic bag, swings to and fro on its padded hanger. All that poor Myrtle’s bringing home is a broken heart and knowledge that her once perky hiny has taken a permanent trip south.

“It is one of life’s cruel little jokes that you’re sailing along thinking everything’s shipshape, when suddenly one day you glance back over your shoulder and your stern is dragging bottom like an anchor,” I tell Spouser later before bed. “They’ll raise the Titanic before Myrtle’s tub ever floats to sea level again.”

I look into my jewelry box, searching for the fake pearls I think might go nicely with the Christmas dress.

“Oh, haven’t I told you yet?” Spouser says. “I found out this year’s Christmas party is only for employees. You’re not invited.”

All this trouble and — I’m not invited!

My black dress is ready to be returned, hanging in the back seat of my car. Before turning out the light for the night, I text Myrtle to ask if she’ll join me for cheesecake and White Russians at Chili’s the night of Spouser’s party.

“Wouldn’t miss it for the world!” she texts back right away, seemingly fully recovered from her gloom.

Hey, you can now join Gina Tiano on Facebook! She is the author of Life in the Bike Lane, available at Amazon.com.