I remember the first time I saw my mum attempt a body roll. The room was lit with multicoloured fluorescent flashing bulbs and we weren’t alone – we were in a Zumba dance class with 40 other bodies sweating it out in activewear. And there was my 61-year-old Chinese mum, coiling her torso back and forth like I had never seen.

I had been to Zumba before but had dismissed it as a novelty exercise featuring a giddy instructor in a wireless headset and clashing prints. But, in this unassuming gym in Melbourne’s south-east, it felt different. The odour of sweat was the same, the dance routines were familiar, but in the front rows of the class were a dozen or so Asian “aunties” – middle-aged women – gyrating their hips in time to the music.

Zumba is unapologetically sexy. No dance session is complete without a chest shimmy, an air booty-slap or a “slut drop” – a dance move that involves squatting as low as possible, before quickly popping upright. “You don’t expect to see a 70-year-old Asian lady twerking,” says Mechelle Felipe, a Zumba instructor at Crunch Fitness in Springvale.

For many middle-aged Asian women, the freedom to explore their sensuality has been limited. Sexually conservative attitudes are prevalent in many cultures across the continent, meaning that for some, sexual exploration hasn’t been encouraged, or has been dissuaded altogether.

But it’s a different story in Felipe’s class, where more than half the members come from an Asian background. “Especially in Springvale, a lot of Asian women are not very expressive with [their sexiness],” says Felipe. For one hour, the class is a safe space for the women to “let loose”.

Clad in Zumba’s signature neon tank tops (which come emblazoned with motivational statements like “get up, get down, get happy”) and the odd miniskirt, these women aren’t here to fade into the background.

One of Springvale’s regular Zumba-goers, Thida, 50, says the classes have given her a sense of freedom. “It encourages us to let it all go and be sexy … It is liberating because we don’t do that in any aspects of our personal life – being sexy and dancing sexy. It gives us confidence.” Reflecting on her Cambodian, Chinese and Vietnamese upbringing, she says dancing was rare. “Even if we went to parties or other people’s weddings, [dancing was] very, very formal and non-sexual.”

Another class member, Jenny, 52, agrees. “Way back then, we don’t dance,” she says. She’s been going to Zumba for more than a decade, and is undergoing a course to become an instructor. “It motivates me a lot and gives me more energy,” she says, adding she’s “a lot happier” and has made many friends. “It’s my passion.”

Diem, a 66-year-old Vietnamese-Chinese woman, is less focused on how sexy the moves may be and more focused on nailing the routine. Speaking in a combination of Cantonese and Mandarin she says, with a laugh, she’s often stuck on the first and second steps, while the class has already moved on to the third step. And she’s adamant Zumba is not dirty dancing – rather, all the joyous hip-shaking and twerking is how dancing should be.

Over the past four years, this army of aunties has come together by chance. None of the members had known each other outside of the dancefloor. Now the regulars have become a tight-knit group. Together they celebrate birthdays, mourn deaths and hang out on weekends with their partners – they’ve even been on a girls’ trip to Queensland.

Felipe has been teaching Zumba for nine years, and has noticed the changing face of the dance regime. While it has its roots in Colombia in the early 2000s, Zumba has expanded to include Bollywood, hip-hop, swing and ballroom dance influences. And like its group members, Zumba’s upbeat soundtrack has diversified. Felipe – a Filipino-Australian – sometimes adds Philippine songs to her setlist; she knows another instructor who included Chinese tracks during lunar new year, and K-pop makes regular appearances in some other studios.

But in Springvale, the most apparent change is in the Zumba dancers themselves. “I’ve seen people quite shy in the beginning and now they’re just so confident,” says Connie Krol, group fitness coordinator for Crunch Fitness Springvale. “They’ve lost some of their inhibition. It’s just incredible to watch.”

As for me, I grew up in a household where I never saw my parents kiss on the lips, physical affection didn’t come naturally to them, and the “sex talk” was nonexistent. But after just a handful of classes, Mum and I have taken to practising our krumping in front of the bathroom mirror together. I’ve shown her YouTube tutorials; she compliments the suppleness of my moves. I love seeing Mum excited about trying new things, and I’m proud to be there, chest-popping alongside her. And she’s even thinking about picking up one of those neon tank tops for future Zumba classes.