Author EL James's "mummy porn" trilogy has aroused a new market that has, internationally and locally, cleared sex shops of accessories used by the main characters, Christian Grey and Anastasia Steele.

Internationally, the novel gave rise to a 400% spike in the sale of sex toys and led to a shortage of ben wa balls, which feature in the book.

Locally, women who would previously have turned 50 shades of red at the mention of sex toys, are now spending hundreds of rands to live out the sexual adventures of the millionaire Grey and his naive college student lover, Steele.

Co-owner of The Bedroom, a boutique for women in Umhlanga, KwaZulu-Natal, Chantal Edouard-Betsy, said there had been an upswing in business since the book became available online.

"We started to see an upswing in March, before the book was available in South Africa. By June, it became absolutely evident that the book had something to do with it and that this was just the start of something new. January and June are usually our quietest months but this year June was the fourth-best month of all time," she said.

Women, some in their 90s, walk into the upmarket boutique and use sign language to ask for the stimulating ben wa balls.

"Some women walk into the store and ask for whips and blindfolds but then there are others who stand at the door and hold up their hands to show they want the balls and we immediately know what they are talking about. Fifty Shades of Grey has started a worldwide conversation and it is really a mania," Edouard-Betsy said.

"Women who have read the book are becoming aware of their sexuality, and of accessories and toys to enhance this new-found sexuality. The book reminds women that, though we are wives, mothers and professionals, we are sexual creatures as well," she said.

Edouard-Betsy believes that the acceptance of the book has helped women move away from being ashamed of erotica.

"Because the book is not hidden in the back of a book store, women know they do not need to be ashamed of reading it. Instead, they are embracing it and their sexual desires," she said.

One such woman is a 46-year-old Durban mother. After being seduced by the book in the space of an afternoon, the beautician raced out to The Bedroom.

"I surprised myself and my husband. When you have been married for over 20 years, spicing up your marriage is daunting. I don't think I would have done it without reading Fifty Shades of Grey. It sounds corny, but it did change my life," she said.

Edouard-Betsy said Fifty Shades of Grey boosted both erotic fiction and sexual exploration.

"Everyone is waiting for the next best thing because EL James has now created a new genre.

"This is not a phenomenon that is going to go away. There is talk of a movie based on the book. Everyone is waiting in anticipation.

"If the book could have such a huge response, imagine what it would be for the movie."