Back in 1976, when Chad Braverman’s father, Ron, invested a small grubstake in a manufacturing start-up, consumers bought his products at the back of seedy bookstores and scurried out with their purchases concealed in brown paper bags.

Afraid of taking on massive debt, a growing number of college students are turning to an unconventional source to pay for school: sugar daddies.

It's white, about twelve inches long with a bulbous head and a couple of buttons, and it became an icon of sexual liberation in the 1970s. It's the Hitachi Magic Wand and, though it's name has since changed, it's still one of the most popular vibrators on the market today, available in brightly-lit boutique sex-toy stores across the country. Forty years ago, women bought their "personal massagers" at the local department stores, hoping the sales clerk wasn't going to give them a dirty look. By the mid-1970s, though, women were tired of these awkward transactions, and a few of them decided to take matters into their own hands, opening the first "women-friendly" sex-toy stores.

Lynn Comella had been attending the annual adult video convention in Las Vegas for years, but she remembers the 2008 event as being unusual.

Nowadays, sex-positivity is mainstream: Amazon sells vibrators for as little as a few dollars, and the honest, open-minded sex-advice podcast Savage Love is consistently at the top of downloads charts.

It all started with a shipment of sweaty sex toys. It was a hot and humid day in August 2003 and Jennifer Pritchett and her then business partner were days away from opening Minneapolis’s first feminist sex shop, Smitten Kitten. They had sunk all their money into their first shipment of products, but as they excitedly opened the boxes of toys, packing peanuts flying everywhere, they knew immediately that something was wrong. The toys were leaching an oily substance. It was coming off the products, out of the clamshell packaging, through Styrofoam packing peanuts, leaving big greasy spots on the cardboard box. What, they wondered, was wrong?

When 26-year-old Amber, a Las Vegas transplant, realized her dog ate her favorite vibrator, she headed to Las Vegas’s Adult Superstore. Amber grew up in a small Midwestern farming town of 6,000 people, a place where sex “was shunned” and sex toys were never discussed. If she wanted to find a sex-toy store back home, it would mean driving 40 miles to St. Louis. Now, at the Adult Superstore, a large sex-toy emporium — think clothing retailer H&M but for sex toys — she knows that she’ll not only have many options to choose from, but once there, she’ll be treated with respect by a knowledgeable staff. But it wasn't always this way.

You never forget your first vibrator. According to a 2009 study by Indiana University, almost 50 per cent of American women have played with the pulsating devices. That number has undoubtedly climbed thanks to pop-culture phenomena such as Fifty Shades of Grey and marked changes in the “adult industry”. Gone are the days when all sex shops were dives hawking crotchless polyester knickers and sticky men’s magazines, with a dodgy peep show in the back. The sex-toy business has boomed into a purportedly $15 billion (£11.5 billion) a year trade that is increasingly high-end, sophisticated in design and aggressively courting female consumers.