If you pull into a South Nowra arcade on a Friday afternoon, the first thing you'll hear is laughter.
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The source of the giggles is a padded room, full of women in pyjamas man-handling one another under the supervision of a Welsh drill-sergeant, also clad in pyjamas.
It's not a madhouse - although if you asked the Welshman he may tell you it feels like one at times.
It's a women-only Brazillian Jiu Jitsu class. The martial art involves wrestling, chokes and joint-locks. The uniform is a traditional gi, or kimono, and the women have taken to the sport with gusto.
A regular crowd of between six and a dozen women, aged from their teens to their 30s, turn up each week to wrangle each other into uncomfortable positions.
Some began because they were sick of watching their kids have all the fun; some young women started to feel safe when they're out alone.
Alex Kastellorizios is a university student in her 20s, and started jiu-jitsu to give her a sense of safety when out alone.
"It has one hundred per cent given me that," she said.
Others started to improve their fitness or build confidence, such as diminutive Ally White, who routinely dominates larger opponents.
Ally is a proud mum who loves to sew when she isn't on the mats.
"I started jiu-jistu because I wanted to build confidence - I think it worked," she laughs.
Some just really like to choke others.
All of the women agreed it was the sense of camaraderie that kept them coming back.
They share a bond forged through sweat and laughter, as well as the occasional tears shed over a particularly gruelling warmup.
Despite the full-contact nature of the sport, blood is unusual.
"The girls are really kind and friendly, and it's a safe environment," said Sandra Turnell, who has also dabbled in karate and is her sons' biggest cheerleader at the cricket each weekend.
Tasha Leeson sports a brightly-coloured mohawk. She was looking for a contact sport that wasn't football when she found jiu-jitsu, and said the supportive group kept her coming back.
"I've made so many friends here, it's a great atmosphere - it feels like family," she said.
Laura Bruzzesse's son and husband both train mixed martial arts - not one to sit on the sidelines, she enjoys a mixture of striking and jiu-jitsu to keep fit.
She summed up the feelings of the group: "I just love everyone here."
The Welshman - coach Jay Golding - said he too began to train jiu-jitsu after his son took up the sport a decade ago, and found benefits of the sport include stress relief, fun and fitness.
He wanted to help women overcome some of the challenges of beginning a full-contact sport, so they could experience the same benefits.
"I wanted to create an awesome opportunity for all women to just come in and have some fun," he said.
"There's so much laughter in the room - you don't hear that from the men.
"Plus they smell better than the guys."
Mr Golding is compact in stature, and as a result he's better able to teach the women the skills they need to hold their own against bigger and stronger opponents when they feel ready to tackle the mixed-gender classes.
The end of class is marked by handshakes, hugs and a chorus of thank-yous as the women put away their ninja pyjamas and head home, sweaty but happy.
Newcomers are always welcome - if you're interested, contact Kemp's Thai Boxing and MMA gym.