A member of the Vogue Club poses in a room at the swingers club in Barra da Tijuca, Rio de Janeiro. (Phil Clarke Hill/For The Washington Post)

At the Livraria Cultura bookstore on Paulista Avenue, a waiter circulated with champagne on a recent Monday evening as a line formed in front of Gabriela da Silva, 22, who had come to launch her first book, “The Pleasure Is All Ours,” written under the pseudonym Lola Benvenutti.

It is the story of her life as a prostitute — decorated with graphic descriptions of sexual acts, including rendezvous with couples in the “love motels” found scattered throughout Brazil — and also something of a manifesto for sexual freedom, written like a self-help guide.

The reaction has been curiosity, respect and even support — signs of how the wheels of social change are turning in Brazil.

This highly sexualized society indulges promiscuity in its men but looks askance at female sexuality even as it prizes the beauty of its women, argues da Silva, a literature and language graduate. She writes that she enjoys her work, embraces pleasure and gets paid — controversial sentiments for contradictory Brazil, a country that is obsessed with sex but deeply religious, conservative and macho.

At this landmark bookstore, a cultural hub for Sao Paulo intellectuals, these sentiments appeared to hit a nerve. “I admire her,” said Carol Monteiro, 18, after joining the line to buy a copy of the book. Added her friend Suzane Albino, 24: “She had the liberty and strength to do what she wanted.”

Gabriela da Silva has launched her first book, “The Pleasure Is All Ours,” written under the pseudonym Lola Benvenutti. (Photo by Victor Daguano)

Lola Benvenutti began as a blog persona, as da Silva used prostitution to pay her way through college. In an interview the day after the launch, she drew a distinction between her book and a 2006 novel by former prostitute Raquel Pacheco, later made into the hit Brazilian movie “Bruna Surfistinha.”

“The way it was presented was about the prostitute as a victim, who suffers,” da Silva said. “Sex for me has always been very good. I do everything to have pleasure.”

Da Silva said Brazilian society has a problem with female sexuality. “Men make this distinction: A woman who has sex on the first night can’t be taken seriously,” she said. “Women are raised not to have orgasms.”

Brazilian women such as she are increasingly challenging these notions. The country is awash with sexually explicit literature — 200,000 read online the erotic romance “Love Has No Laws,” by first-time writer Camila Moreira, according to Brazil’s biggest newspaper, the Folha de S. Paulo. The paper also hosts a blog, the X of Sex, in which one woman recently detailed realizing her fantasy of having sex with two men at the same time.

Brazil has a very sexually active population, said Carmita Abdo, coordinator of the sexuality studies program at the University of Sao Paulo. Just 8 percent of Brazilian women and 3 percent of men have no sex, according to a 2008 survey Abdo conducted for Brazil’s Ministry of Health. “We are a people recognized for a lot of sexuality. And we end up wanting to live up to this,” she said.

But Brazilians have problems talking about sex, said Jaqueline Barbosa, 25, and Emerson Viegas, 31, who four years ago started the relationship-and-sex blog Shameless Couple. It now has 80,000 visitors a day, they said in an e-mail interview.

“We are seen as a liberal country, because Brazil is very associated with Carnival, the culture of the body, sexiness, TV programs with many exposed bodies. . . . Brazilian people converse very little about sex,” they said. “Women have certainly conquered more sexual freedom, but there is still a lot to be evolved.”

That would include experimentation, as more Brazilian couples visit the swing clubs and “liberal parties” that have long discreetly existed in big Brazilian cities but are now emerging above ground. The Shameless Couple offers advice on how to manage threesomes but cautions that they are not for every couple. “The option has to be discussed, because more and more couples are succeeding in establishing a differentiation between sex and love,” they said.

In a 2011 survey by the international dating agency C-Date, 49 percent of Brazilian men and 19 percent of women said their fantasy was to have sex with more than one person at the same time. In one chapter of her book called “Sodom and Gomorrah,” da Silva describes being hired for an orgy by a group of well-to-do doctors and their wives at a remote ranch. “They were very well mannered, paid me really well; they trusted me,” she said. The women wore heels; the men wore Rolex watches. No one wore anything else.

Earlier this year, André Luiz, a 49-year-old lawyer, opened Apice Club, Sao Paulo’s newest “swing house,” in the upmarket Moema neighborhood, with his wife, Ana Paula, 35. Both are swingers, Luiz said. They plan to invest up to $1.1 million.

“The popular saying is that swing is good. There is just one problem: It is addictive. Those who enter don’t leave,” Luiz said.

The club has a dance floor where couples interact, and a darkened, secluded area out back for sex. On a recent Friday night, couples watched a cowboy stripper or disappeared into the back area.

“It is part of the culture of the newer generation to see sex as something open,” said the club host, Fabio Gouvea, 39. He said 1,100 couples are connected to his profile on a network site. “All swingers,” he said. “It’s very cool.”

Rio de Janeiro’s Vogue Club is a “liberal party” aimed at a younger market. About 400 couples celebrated the club’s first anniversary recently, said Claudio de Luca, 48, one of its partners. The club has a “Cupid” to introduce shy couples to each other on the dance floor.

The night after the club’s anniversary, some of its clients agreed to be interviewed and photographed if names were changed. “I have a life that is not swing, that is of a normal person, who works, who goes to college,” said “Ninfa,” 29, a nutritionist. “There is prejudice.”

“Sandro,” 42, and his wife, “Deborah,” 25, said swingers are reacting against social norms that accept male infidelity but do not allow women the same freedom. “It preaches that a man can do what he wants, go out with as many women as he wants,” Sandro said. “The swinger sees it like this: The rights he has, the woman has.”

Abdo said that young Brazilian adults are experimenting more and that the increasing visibility of clubs such as Vogue and Apice has heightened curiosity.

“Experimentation is much more common today — hetero, bi, homo, sex with more than one person,” she said.

But the fundamental shift in sexual behavior, Abdo said, has been among women, who start their sex lives earlier, marry later and demand more of the men with whom they have physical relationships. “The man has to be always ready, if he is seduced,” Abdo said. “She is more demanding and does not just have sex to give pleasure.”