Guilty secret or not, steamy fiction is a favourite literary genre of many a hot-blooded woman. Or so the runaway success of Fifty Shades of Grey suggests.
According to the Daily Mail, the BDSM (bondage, discipline, sadism, masochism) novel is currently sitting in 28th place on the New York Times bestseller list and is topping Amazon and Barnes & Noble charts.
It is so popular that a single paperback copy is currently listed as costing $999.99 at Amazon, though a Kindle version is available for $6.99.
It's also topping conversation topics on school runs, on well-heeled Caribbean holiday beaches and on the sidelines of Saturday morning sports practice, according to the New York Post.
The raunchy novel has become a favourite with Upper East Side housewives who are devouring the book's blue contents and fiendishly recommending it to friends.
Publicist Alison Brod told the newspaper that the novel is 'the new Kabbalah for female bonding in this city' - and is spreading its X-rated charms. 'I found myself explaining what BDSM was to some of the moms at Saturday morning basketball.'
One 40-year-old mother-of-three said that Fifty Shades is 'just a fun escape from the daily mundane of trudging kids around and, you know, marriage'.
Having started posting BDSM fiction online, author EL James piqued the interest of small Australian publisher, The Writers' Coffee Shop, who took a leap of faith by publishing Fifty Shades of Grey in May 2011, followed by Fifty Shades Darker and Fifty Shades Freed, on sale since January.
The newspaper likens the story to Twilight for grown-ups, suggesting it has become something of a cult tome among mothers, who, according to New Jersey mom, Alyssa Goldman, call it simply 'The Book'.
She admitted that 'kids have never seen their mothers reading so much' and a favourite gift for her friends' husbands this Christmas was silver ties - as worn by Christian Grey in the trilogy.
Mr Grey, a 27-year-old billionaire, seduces young graduate, Anastasia Steele. He has a penchant for bondage and soon envelops her in a world of kinky sex, S&M and XXX-rated bedroom 'contract' games that make for solid post-watershed reading only. Love, inevitably, is not omitted from the romance.
Readers at Amazon froth over Mr Grey's 'brooding', 'masterful', 'intimidating' character. Ms Steele is clumsy, inexperienced but crucially, 'not naive'.
But it's not the brilliant literature than has people's tongues wagging - and cheeks flushing.
Pam, another Upper East Side mother, told the Post that Fifty Shades 'totally makes you horny ... I think everyone has totally admitted to that.'
That 'everyone' includes Dawn, a 27-year-old who lives in New York's Financial District. She told the newspaper that the book is blush-inducing.
'Every time I pick up this book,' she explained, 'within five minutes of reading it, I’m already tingling below the belt.'
The Upper East Side local said: 'The person who recommended it to me said, "It will make you want to have sex with your husband." And it did!'
She is not alone - another mother told the paper that the book is having the magical effect of boosting sex lives across the well-heeled neighbourhood.
The piece of erotic fiction is no convenient handbag read - its 1,200 pages, an armful in itself, is laden with steamy writing that makes it far from easy to read in public places.
Fans, mostly women, are getting around the issue by buying the Kindle edition, and 90 per cent of the trilogy's 100,000 sales are e-books.
Another Upper East Side mother said that while she found the writing 'a little lame,' she still 'got into the story. I really became a cheerleader for their relationship.' Not enough of a cheerleader to include her name - the Post reports that she wished to remain anonymous as she did not 'want my doormen knowing I read this book'.
That is not to say men aren't enjoying the Mr Grey and Anastasia's kinky antics, too.
A 47-year-old unnamed divorcee told the newspaper: 'I didn’t think it was a great book as far as writing goes ... But it was a fun, enjoyable story ... I enjoyed parts of it. The erotic parts. I found those to be interesting.'
Ms Brod said: 'A guy friend of mine said he wanted to form a business looking for girls who have "just finished the book, before they cool off.'"
There should be plenty of them about - the book continues to be snapped up online and Ms James - who says she is 'gobsmacked' and 'blown away by the popularity' - is currently working on another instalment.
Patricia Bostelman, vice president of marketing at Barnes & Noble told the Post that the book's U.S. popularity - which bubbled up around Christmas time, later than other English-speaking markets - 'was a New Year’s surprise.'
Many husbands may agree.