There’s a barefoot middle-aged woman with a gray buzz-cut flailing around the living room to the melted cheese of Frankie Valli and the Four Seasons’ “Can’t Take My Eyes Off You.”

“What are you doing, Mom?” my kids ask. It is obvious — at least to me — that I am dancing.

I swoon, “Isn’t the horn section divine?” I shake invisible maracas. Then I switch to the Kinks’s “Come Dancing” and kick up my heels.

My kids eye me curiously. Mom is… happy. Mom is… aglow?

I’m usually grim and scowling. There isn’t enough Botox in the world for my Resting Mom Face.

As a middle-aged mother, the phrases “life improvement,” “life optimization” and “happier” make me frown even more deeply. I’m allergic to self-improvement. I’ve resisted prescriptions for a happy life. But when I read that Gretchen Rubin, the author of “The Happiness Project,” suggested dancing as a key to family cohesion, it struck a chord.

I used to love dancing.

In my footloose 20s before I had kids, I went to many a Noche Latina in the Boston area in my salsa shoes with a daring two-and-a-half-inch heel. I cha-cha-ed. It was the ’90s, and Big Band was back, and so I swung. I Lindy hopped. I went to Adult Dance Camp and it was not ironic. I sprinkled dance sand on the floor.

On the dance floor I did not excel, being neither naturally talented nor graceful. But I was enthusiastic. And I had a good sense of rhythm.

I wore the kind of big eager goofball overbite smile of happiness that people associate with the drooling puppies of large dog breeds. I was a good time. Fun. I sang along with Dinah Washington: “Since the world is round we’ll be safe and sound / ’til our goal is found we’ll just keep the rhythm bound.” Preach, Dinah, I said, doing a swing out with loads of verve, my swing-kids’-style skirt belling.

When I was dancing I was at my — dare I say it? — happiest.

When, in a tango class, the instructor instructed me across the dance floor, I felt in my heart the Big Red Balloon of Joy expanding and I felt like I was falling in love with him and I whispered into his ear as he held me to his chest, “I think I love you.” “Well,” he said, in his Argentine accent, making light of the moment with a this happens to me all the time shrug of his shoulders: “That’s the power of dance.”

Dance does have power: It makes me more loving.

When I got married (not to the tango teacher) and had kids, suddenly there were so many other things besides tango and salsa heels and perfecting the swing out that were important. Motherhood sidelined me. I abandoned the dance floor and lighthearted Terpsichore and became like one of the lesser Greek goddesses who tends the hearth and no one knows her name. Hestia? Whatever.

I became super serious. Motherhood was serious business. It was no disco. There was the right school to be chosen for the right reasons and math facts flash cards to review and orthodontia. My salsa shoes cobwebbed. So did my delight, though very occasionally I would frug around the kitchen with my daughter and give her a whirl to the Squirrel Nut Zippers. “You’re smiling, Mom” she’d notice, in other words asking, Who are you? because usually I could pass for the famously grim migrant mother of Dorothea Lange’s dust bowl portraits.

I noticed it too. The change in me. The dance-induced euphoria. The ballooning of my heart in my chest. The relaxation of the lines between my eyebrows. The urge to do the Twist. But I would shut it down, snap out of it, turn off the music, and return stiff-backed to checking homework and dialing affordable academic-minded summer camps. Motherhood was no “Flat Foot Floogie” routine.

But why not?

Where had I learned that motherhood was about moving cautiously, and not moving my feet to the beat?

Perhaps because middle-aged motherhood tends to be a place of creative tension around women’s bodies. Cankles and muffin tops. Spanx. We are supposed to talk about our bat-wings and our lost youth and joke about caftans as we swill white wine from vats and weep a little. There’s the middle-aged mom archetype: prim, chaste Dance Mom, who pins her daughter’s hair into a ballerina bun, and chauffeurs her to recitals. Or, alternatively, the cougar who takes pole dance lessons. I just want to dance.

So I put aside my concern that I have cankles and that I’m not 28 — who is? and furthermore, who cares? — and joined a Rueda de Casino, a Cuban-style square dance in Baltimore.

Here’s what the other middle-aged mothers I dance with look like: kinda sweaty. Jiggly in bits. Ecstatic. Quotidian. Universal. Like a bunch of aging spring goddesses. I could wear my old salsa shoes (they still fit), but I’m barefoot because it’s easier on my knees.

I tell the kids, “What do you mean what am I doing? I’m dancing! Join me!” My arms are wide open. I have the Newfoundland-puppy, dance-induced smile on. It’s what was missing from motherhood: joy. Get up on the downbeat.