Performing yoga in the nude does unkind things to the male body.
The human scrotum looks miserable enough at the best of times, but I've never seen mine look as demoralised as right now.
Our instructor - also naked - has told us to stretch our right leg tightly over our left, before twisting our torsos to flex out our spines. If I was wearing underwear, this would be easy. But because I'm nude, this scissored, clamp-legged position just bunches my equipment together and mashes everything upwards, until it resembles some sort of angry offal bouquet. And I thought yoga was supposed to be beautiful.
I've come to my first Naked Yoga class to suss out its appeal. Considering these classes requires everyone getting buck naked in a group to stretch in every conceivable position, surely it can't just be about the yoga, can it?
Sessions run on the second floor of a warehouse in Sydney three times a week and, on average, attract around 15 men every session. No women are allowed. Nude co-ed yoga classes are taking off in the US and UK, but in Australia, only all-male classes exist.
Naked Yoga Sydney's instructor and founder, Steve Gee - who started his classes nine years ago - tried reaching out to women in the early days, but found there just wasn't the demand.
"I've had a few enquiries from women, looking for either women-only classes or mixed classes," Gee says, "but not enough interest to justify running a full-time class."
Nude Yoga USA in Arizona, which runs co-ed naked yoga classes three times a week, has some theories as to why women might be more shy. In their classes, men can outnumber women four to one.
"Personally, I think females just aren't as interested in nudity as men," says co-founder and assistant instructor Lori Leatherman.
"Guys just want to see something naked - they don't care! Plus, women are afraid to be judged. Women tell me, 'Oh, I'm just not comfortable with my body.' Even women who go to the hot springs nude still say, 'I don't know if I could do nude yoga.' They're afraid of the postures. Guys are afraid of getting an erection in class. Women are afraid of someone seeing everything. No woman wants to do downward dog with someone behind them."
This is why Nude Yoga USA conducts its classes in an inward-facing circle.
Does this mean most of the guys at Sydney Naked Yoga are gay? Founder Steve Gee says he doesn't ask students about their sexuality, but suspects there are more gay guys than straight.
Ultimately, though, he suspects most students are like him - nudists who just happen to enjoy a bit of downward dogging.
When I step inside the class, I baulk - not because everyone is naked (at least, not yet), but because there are floor-to-ceiling mirrors lining the front wall.
Immediately, I lay out my yoga mat in the back corner, closest to the exit and as far as possible from my own reflection.
This isn't out of shyness. Travelling in Japan and using traditional bathhouses demolished any problems I have with public nudity. I just don't want to inflict the image of my naked form bent over in cow position to a room full of strangers. It seems like bad manners.
Before the class starts, I ask Gee - a warmly spoken, strapping-fit bald man - the obvious question. What happens if you get an erection in class? It's the most common thing first-timers ask him.
"From time to time, someone will get an erection," he says. "My take is, 'We're all guys, we're all healthy males, erections are a part of being guys. If it happens, just keep going with the yoga.' What you'll find is very quickly, the erection will subside. But it's nothing to be embarrassed about. I've never run anyone out of the class for getting an erection."
But surely, some people just come to perve, right? Gee says he filters people like that out.
"Firstly, I make it quite clear what the aims and objectives of the class are. Secondly, I have a nudity-mandatory policy. No one who wants to leave their underwear on is allowed in - everybody must be on a level playing field."
Gee says he's been running the classes long enough to suss out any ulterior motives. "It's in the types of questions they ask. Like, 'Do I have to take my clothes off?' 'Can I come along and just watch the class, rather than participate?' 'Is there any touching?' " If men ask those questions, he tells them gently, "I don't think this is the type of class you're after."
In the warehouse, heaters have been turned on to combat both the cold and potential embarrassment, and the room is candle-lit. It can't be all that pervy, I figure - we'd have to squint hard during class to cop a decent eyeful.
More men stream in - there are roughly 20 of us now - and we stretch out casually, still clothed, on our yoga mats.
Guys in their 40s discuss their home renovations. A trim-looking man in his 20s keeps to himself and stares at the floor, while chatty seniors nearby discuss recent injuries and back pain.
"People ring me or email me and say, 'Look, I'm a middle-aged guy carrying a few pounds around the middle, and I'm not all that flexible. Am I going to be the odd man out?' " says Gee. "And the answer is, 'No.' If you walk down the street and look at every bloke you pass, it's a fair indication of the type of guy who comes to naked yoga."
Finally, Gee shuts the door. That's the cue. Before I can register what's even happening, everyone around me quietly takes off their clothes and returns to their yoga mats, completely naked. Not wanting to be left behind, I hurriedly strip off, cast my eyes downward and sit back down, too. And we begin.
It's likely that no other form of exercise has been subjected to as many bold experiments in cross-breeding as yoga.
Besides yoga's traditional forms - Iyengar; hatha; ashtanga; vinyasa - there are common modern variations, like yoga performed in artificially hot rooms (bikram) and yoga fused with Pilates (yogalates).
Around the world, there are other bizarre hybrids, some of which sound like a recipe for spinal-cord injury (horseback yoga; surfboard yoga), and ones that make no sense at all (yoga raves; yoga pole-dancing).
There are yoga classes for dogs, yoga classes for mothers with newborn babies, and one class in Los Angeles that encourages students to arrive high on marijuana.
"People try to blend everything with yoga," says Leigh Blashki, president of Yoga Australia. "Acro-yoga, this yoga, that yoga." But, he adds, "We're not exclusionary. We like to include any possibility."
Does that include nude yoga? Blashki laughs. "Well, it's not something that's drawing me in, and that's not from prudishness. But yoga emphasises steadiness and comfort, and if a person feels they can be steady and comfortable doing it naked, without being distracted by their own sense of self or other people's looks ... personally, I'd find that difficult, but in theory it's possible. I've taken my clothes off in my private yoga studio to see whether I could practise."
What happened? "I felt ... uncontained. Like, 'I better be careful here, because I might squash something!' And then there are other issues." He pauses. "Hygiene issues."
For what it's worth, Gee encourages students to bring their own towels and yoga mats to his Sydney class. But at Melbourne's Gay Men's Yoga, however, our instructor has told me to bring nothing to their monthly clothes-optional class in Collingwood.
As a result, I'm using a yoga mat I'm pretty sure has been used several times over. By the time class starts, I really regret not bringing my own towel.
The Melbourne naked yoga class isn't that different to the Sydney one, except it's slightly colder and the men have more tattoos and facial hair.
Plus, the explicit "gay" focus means the classes also feel a little bit ... well, gayer. "Keep holding that breath," our instructor quips, "or I'll come over and smack you with a bamboo stick!"
Personally, I'm happy to hold my breath: the man behind me is emitting some breathtaking BO.
"And be mindful of the person next to you," he adds, "unless you want to reach out and touch somebody."
"Like Diana Ross!" someone says. Everyone laughs. Then we assume a position where we lie on our backs, hold onto our toes and stretch our thighs out wide. I feel like a dead chicken about to be stuffed.
"Let go of the things inside you," our instructor says. "Let go of people ... situations ... stresses ... foods ..."
"Dear god," I think, hoping the others can read my mind. "Can we please make a pact not to let go of our foods?"
Personally, this is possibly the least erotic position I've ever assumed in my life. Still, one young man in the room can barely disguise his semi-erection throughout the class.
Given the nudity, it's difficult to deny there isn't some sort of low-level sexual buzz in the room. Naked-yoga instructors insist their classes aren't about sex, but search "naked yoga" online, and interspersed between all the legitimate classes are a slew of porn websites, and others that veer close enough.
Hot Nude Yoga, the US brand that first made naked yoga into a big business, sells videos with titles like Getting Undressed with Hot Nude Yoga, Double Your Pleasure and The Beginners Class - Virgin. One DVD cover features a toned yoga instructor correcting a student's position suggestively from behind.
At the same time, nude yoga - a completely modern invention - also feels like a salute back to a more innocent time when naked male group exercise wasn't particularly odd.
In the ancient Olympics, between 776BC and 394AD, male athletes performed naked. From the late 1800s to the 1960s, swimming without bathers was required at YMCA pools in the US, because stray wool from thick bathing suits clogged the primitive filtration systems. It only takes a few minutes before it feels completely ... well, natural.
Towards the end of my Sydney class, Steve Gee looks down to correct one of my postures. He does what every good yoga instructor does: straightens my back, changes the angle of my arms. The only difference is his penis is hovering over my head. After a warm-down and meditation, just like that, the clothes are back on. It's namaste and we're out.
"That wasn't so bad," I think, rolling up my mat. At least I didn't have to buy a new outfit.
- Daily Life