There are no signs outside this backstreet brothel at the heart of China's 'Sin City', just a shadowy alleyway, two metal gates and a pimp named Crow.
Inside, on the five-storey villa's ground floor, six prostitutes in fishnet tights and bright red lipstick are slumped onto a sofa, munching on noodles under the pink and blue glow of neon lights.
"The police won't trouble you," said the pimp, who was wearing a bright yellow Sweden football shirt and asked for 300 yuan (£32) for a night's entertainment.
This is Dongguan, a sprawling factory boomtown in the Pearl River Delta that boasts a population of around seven million people and a reputation as the Chinese capital of sex. For a price here, anything goes.
Estimates about the scale and reach of Dongguan's underground sex trade almost beggar belief.
Between 500,000 and 800,000 people – some 10 per cent of Dongguan's migrant population – are in some way employed in the world's oldest profession, according to Hong Kong's South China Morning Post.
A staggering 300,000 sex workers – known locally as "technicians" – are thought to ply their trade in thousands of side-street massage parlours, exclusive hotels, spas and neon-lit karaoke bars.
"Many wives feel anxious whenever their husbands take business trips to Dongguan," the city's former party chief, Liu Zhigeng, admitted in 2009. "It's disgraceful."
Intent on shedding the city's image as China's capital of sleaze, authorities are now going on the offensive.
A slick new propaganda campaign seeks to recast this grimy manufacturing hub city as a picturesque cradle of culture and diversity.
"Upon coming to Dongguan, the first thing I notice is that the local people's lives are deeply rooted in traditional culture," gushes the voice-over for one PR film, reportedly produced by the Discovery Channel and aired across China. "The city has an inherent charm, warmth and an amalgamation of cultures. Everyday, the city manages to excite."
Security forces are also chipping in, trying to push prostitution off Dongguan's streets with a "sweeping yellow" crackdown on a trade that was outlawed in China following the 1949 Communist takeover.
Last month, the 'New Generation' sex market on Dongguan's outskirts became the latest red-light district to receive a visit from the local constabulary.
The outdoor market – a tatty labyrinth of concrete car garages that once served as mini-brothels – now lies abandoned. Dozens of shacks have been shuttered and Public Security Bureau seals adorn the metal doors where prostitutes once loitered.
"They closed the market last night," complained one local 'madam', a woman in her thirties wearing a red tracksuit top. "Normally, we could find you two girls for 150 yuan (£16)." Dongguan's sex trade may now be less visible than before but many thousands of sex workers still operate inside underground venues that are an open secret to those in the know.
On the second-floor of one of Dongguan's ubiquitous KTV karaoke bars, two elegantly dressed hostesses paraded dozens of girls before their visitors.
At least one appeared to be under-18.
For 300 yuan, the girls were available for a night of drunken karaoke, fuelled with beer, whiskey and Turkish cigarettes. For 1,200 yuan, guests could retreat to their hotel rooms with the girls.
"I'm married and have a 22-month-old son," said a 28-year-old KTV girl who was starting her third day at the club and gave her name as Luo. "My husband doesn't know I work here, nor do my parents." Luo said her route into prostitution had begun in the casinos of Macau where she racked up debts of nearly £80,000.
"I have no other option. I will leave this place after I earn 20,000 or 30,000 yuan and I'll probably return to the casino to try and win it back." A girl from Jiangxi province who gave her name as Tong said a friend had tricked her into swapping a job at a nearby shoe-factory for the KTV bar.
"I had no idea what business was going on here until I came," said Tong, who claimed she was 19 but appeared no older than 15 or 16.
Similar stories could be heard across town, in a roadside massage parlour, strategically located opposite a suburban zip factory. There, three girls were perched on a sofa beneath three fake pink roses that had been taped to the wall. A small television in the corner beamed CCTV images down from the second floor where "special massages" were administered.
Ling Ling, who said she was "20-ish", came to Dongguan from a village in Guizhou, China's poorest province, to work at a toy factory.
Soon, however, she decided she could make a better living out of the massage parlour. "I have no choice. I have to support my family," she said.
Another sex worker, who gave her name as Juan, said she had been forced into prostitution after her shoe factory boss eloped with the workers' wages.
"I prefer working in a shoe factory," she said. "At least there I can earn a living with my hands. Here, I have to do it with my body." Local newspapers have celebrated attempts to give Dongguan a much-needed facelift. One micro-blogger, quoted by the *Yangcheng Evening News, said the campaign was *"a slap in the face to those who bad-mouth Dongguan." But asked about their city's campaign to eradicate prostitution, the massage parlour "technicians" shrugged.
"I heard there have been crackdowns recently," said Ling Ling. "But the police haven't bothered us."