Flash-lit by synchronized lasers, a nightclub heaving with Hong Kong teenagers vibrates to the latest dance hit as a pair cavort on stage dressed in the skimpiest of outfits.
"Scream louder if you want more," a DJ shouts to the cavernous hall, while on stage the male dancer in low-cut jeans throws his female partner onto his lap in a frenetic routine in time with the music.
It's a typical Friday night, but while many of the clubbers hail from Hong Kong the venue itself is not in their home city. Welcome to Shenzhen, across the border in mainland China and an increasing draw for young people from Hong Kong in the 10 years since the former British colony was handed back to Beijing.
Shenzhen is cheap, it's vibrant and it's close -- and crucially for many of those who regularly make the weekend trip, it's a good source of recreational drugs. "I'm so used to going to Shenzhen," said Ah Yan, 19, who often travels up with groups of 10 or more.
"My friends and I go there every week because it's close and convenient.
They don't check your ID and you can buy drugs from the bouncers." It was at a Shenzhen club that she was first offered ketamine, a so-called party drug to which she later became addicted. Club owners here target the Hong Kong market because they can afford higher entrance fees than local people and drinks that cost three times more.
"Most of our customers are from Hong Kong as local people cannot afford our drinks," said one manager who called himself Ah Kit. "We have people who come late, stay here until early morning and go back to work the next day." They also appear to appreciate easier access to illegal drugs.
"There weren't that many people in these clubs in Shenzhen when I was 14, and now there are a lot more of them," said Siu Bak, now 23, a regular visitor who says she has been abusing drugs since she was 13.
"Be honest, we go there for the drugs. Ten out of 10 do that." With police in Hong Kong police frequently checking clubs there, Shenzhen has become a better choice, Ah Yan said. As well as a more relaxed attitude to drugs it also offers bigger and more modern venues and an under-age entrance policy that is virtually non-existent.
Although this Shenzhen club has a heavy presence of bouncers and security guards, in uniform and plain clothes, Ah Yan said they are the ones who supply her and her friends their favourite drugs, ketamine and ecstasy.
Using drugs over the border is a trend that is increasingly worrying social workers in Hong Kong. According to official figures, the number of Hong Kong people arrested for using drugs in southern Guangdong province, where Shenzhen lies, rose from 191 in 2004 to 336 last year.
Over the same period, the number of people under 21 arrested in Hong Kong for drugs offences fell by 24 percent to just over 1,000. Chu Fung, project manager for a programme called PlaySafe aimed at raising awareness of the health risks of drugs and unsafe sex at Hong Kong clubs, said going north for drugs began with the rave culture that came in from the West.
"That's when party drugs began to get popular among the youths here. They follow it because they believe it's a new fashion, they don't see it as drug abuse," he said. "Because of the police crackdown on Hong Kong discos," Chu added, "many of them go to China to take drugs.
The biggest challenge for us is to reach those youths." That has also been reflected in the popularity of certain drugs. In 1997, the year Hong Kong returned to Chinese sovereignty, there were a recorded 1,855 heroin abusers. Last year -- according to official government figures -- that had fallen to just 51.
Conversely, the number of ketamine abusers soared over the same period from fewer than six to 1,845 -- it is now the most popular illegal substance -- and ecstasy has undergone a similarly sharp rise. Ah Yan, who said her parents travel up regularly to Shenzhen to feed their own addiction to cocaine and ice, insisted she was trying to quit. Not just yet though. "I've been arrested countless times but you only need to leave a few hundred dollars on the table, they'll let you go."