Decades after Mao Zedong, couples are happy to browse sex toys together – but not all attitudes have changed

"One-two-THREE! CONTROL! … and relax," Ma Jian urges. The 78-year-old author is addressing a few dozen men clustered around a stage in Guangzhou, but he aspires to a much bigger audience. "China has more than 2,000 years of sexual history and culture and skills. It has sexual experience which western countries have never known. I want to introduce its expertise to people here and people overseas and make all men happy," he said.

"I want all women to benefit. I take guys who shoot in three minutes and teach them to hang on for 30. That's long enough."

Until 10 years ago this evangelist was, he said, "an underground worker", toiling in strictest secrecy. He grew up in the sexually repressive society created by Mao Zedong. The chairman of the People's Republic may have shared his own bed with numerous women, but under his rule bodies were disguised in shapeless suits and holding hands in public was shocking.

Even in the 80s, after liberalisation had begun, a man was executed for organising orgies. Now Ma rattles off his advice – swimming increases sexual desire; pee in short bursts, not a stream – at a convention co-hosted by family planning authorities.

More than 30,000 visitors thronged last weekend to the 10th national (Guangzhou) sex culture festival to watch pole dancers, buy 007-brand condoms and browse porn in a resolutely unerotic exhibition centre. Couples take happy snaps with giant virility figures, and unabashed shoppers fondle realistic sex dolls (though not, this year, inflatable Obamas). The wealthiest can even choose a 100,000 yuan (£10,000) solid gold "pleasure object" – the kind of high-class product that appeals to shoppers usually found in Louis Vuitton or Dolce & Gabbana, a sales assistant said.

Men photograph semi-clad models on a catwalk at the fair. Photograph: Dan Chung for the Guardian

But the shots of "artistic nudes" are tame by western standards. And though hordes of men photograph furiously as semi-clad models strut to a disco version of the Old Spice theme, there's no pouting or lip-licking. These days, sexual experimentation and puritanism sit side by side in China.

Qiu Shuang, a lesbian activist and sex toy saleswoman, argued that repression had only kindled passions. "Maybe we seem very conservative, but we have the biggest desires," she said.

China has an estimated six million sex workers, yet nudity is unacceptable in the cinema and there are periodic anti-porn crackdowns. Women have hymen restoration surgery so their husbands will believe they are virgins. Two years ago, an academic was jailed for hosting sex parties. It is no coincidence that the official denunciation of the disgraced politician Bo Xilai accused him of improper sexual relationships with several women.

"People still frown on serial dating … [but] there are 200,000 sex shops and these huge sexual expos. Are they prudish about sex or are they incredibly liberated?" asked Richard Burger, whose new book, Behind the Red Door, chronicles the history of sex in China.

He argues that for centuries China's leaders have swung between sexual openness and repression. In the Tang dynasty, prostitutes were registered; the late Ming saw explicit novels such as The Plum in the Golden Vase.

At times, homosexual love has been celebrated. At other times, erotic books have been burned.

In the west, the sexual revolution was part of a wider movement of personal liberation and challenges to authority. But in China, the post-Mao shift from procreation to recreation was driven not by the Beatles and Lady Chatterley but by the Communist party.

Sex dolls on show in Guangzhou. Photograph: Dan Chung for the Guardian

"After the Cultural Revolution, the government's control [of people's lives] started loosening, and at the same time the one-child policy meant people could have sex lives that weren't for the purpose of giving birth. They could have sex for pleasure," said Pan Suiming of Renmin University, one of the country's leading experts on sex.

Li Yinhe, another researcher, said: "In the past, women were not allowed to like sex – sex was only for giving birth to children, or serving men. Now they can enjoy sex."

When the magazine Popular Cinema dared to print a romantic clinch in 1979, it sparked a national controversy. The publication of the kiss – a still from a Cinderella movie starring Richard Chamberlain – was "decadent, capitalist, an act meant to poison our youths", complained an irate local propaganda official. But thousands more picked up their pens to support the magazine.

But puckering up lost its subversive edge – even if the average age for a first kiss remained at 23 just a few years ago. These days premarital sex is very common and has spread to rural areas too.

Yet even now, most assume that sexual relationships end in marriage. Half the men Pan surveyed in 2007 reported only one sexual partner – and even younger and more experienced men have double standards, as a group of female students at the festival testify.

"There's a long way to go. People do think a woman is a slut [if she has had multiple partners]," said Emily Mai.

"We have a right to chose premarital sex," added her friend Yee Bai. "It's freedom. We can't stand to have only 'pure, spiritual' love."

Sun Zhongxin of Carnegie Mellon University and the University of Pittsburgh says the sexual revolution has benefited different sexes and sexualities to different degrees, and that both men and women may face new pressures, feeling inadequate when faced with a single and sometimes more westernised standard of sexiness.

Tens of millions of men will not find wives or long-term partners at all, because of China's "missing" women: illegal sex-selective abortions have caused the gender ratio at birth to rise from the natural rate of 106 boys per 100 girls to 118 boys.

Many more men are migrant workers who may see their spouses once a year at best. "They can use sexual toys to let their desire out. It's better than going to have sex with prostitutes," said the event's deputy director, Zhu Jianming.

But as Sun pointed out, the sex industry is not just the fruit of changing attitudes; it has been aggressive in pushing "liberalisation".

A local law enforcement official touches a statue at the fair. Photograph: Dan Chung for the Guardian

The results can be alarming. One stall in Guangzhou is advertising a sex doll designed to look like a very young girl.

Zhu dismissed concerns: "It doesn't encourage people … You can't criticise a sexual fantasy."

But he adds that he too worries that some people "have been influenced by western ideas about sex, are out of control and indulge themselves sexually". He insisted the show was designed to encourage sexual morality and positive relationships, not just sexual knowledge.

Though the festival clearly caters primarily to straight men, there are several older couples browsing arm in arm. A husband and wife stop to listen attentively as a salesman demonstrates the different groans emitted by a selection of fake vaginas.

"In the past, when two people dated, they even had to keep their distance on the street," said 25-year-old Li Bo, sheepishly clasping the sex toy he had just won in a prize draw. "Of course we wouldn't want to go back to the old times."

Additional research by Cecily Huang