A poet even called it the "the glittering tart," referring to its status as a tourist destination, its natural beauty, also perhaps to its underbelly of crime, drugs and hedonism.
And so with World Youth Day over and done with, it's time for topless pole dancing, strip poker and female orgasms offered free.
Organisers of the event, which opened on Thursday at the Hordern Pavilion and Royal Hall of Industries, hope to attract a record crowd of 55,000 over four days.
Aside from the usual colourful melange of vibrators, candy undies, fluffy handcuffs, kinky boots and nurses outfits - as well as helpful advice on safe sex and sexual problems - there is plenty of opportunity for active participation, reports Sydney Morning Herald.
Female attendees are offered a free orgasm.
With the help of three pink, knobby, vibrating chairs, Sex Machines Australia will be totting up the number of (fully-clothed) women who orgasm on their electronic scoreboard, or "orgasm counter".
The machine attracts women from 18 through to 70, according to Sex Machines Australia.
"Some girls won't let themselves go ... but if we can get the girl to sit on it, close her eyes and relax for a minute, they'll orgasm ... one girl in Brisbane got up to about 10," a worker at the stall said.
Another attraction gaining popularity is the strip poker tournament.
The winning player receives a $20 Sexpo voucher, and if they get naked they get a goody bag.
So do people often play until they're naked?
"In Brisbane, they were only allowed to get down to their undies," said the croupier.
"But in Melbourne it was great. Heaps of people got naked."
Any remaining World Youth Day pilgrims in Sydney shouldn't feel shunted by the debauchery though.
They get half price tickets into the event and the chance to take confession, not to the Pope, but to top international porn stars.
"It would be fantastic to hear their confessions," said porn star Belladonna from Los Angeles, who has been touring Australia for 12 months with Sexpo.
"We all know the sins are there," she added. "And we wanted to give something back to the Pope."
Tim Patch, also known as Pricasso, has also paid a papal tribute.
Using just his penis, he has created a colourful painting of the Pope at Sydney Harbour, clad in his robes and draped by two sexy, bikini-clad women.
"It's a collage of everything that happened (for World Youth Day)," said Patch, who will be on hand to paint portraits throughout the event.
"The Harbour Bridge, the Opera House, the Pope on his vacation ... he's only human. I'm sure he thinks about this sort of thing."
But the trade show opened without any protesters. Possibly because the sex industry is becoming mainstream.
"We've been really disappointed by the lack of protest lately. We've been thinking of setting up our own protest," Eros Association chief executive Fiona Patten said.
"I think we have hit that point where the vast majority of the population do not see anything all that scary about Sexpo...
"There are so many (television) programs that reflect that relaxed attitude to sex and when you look around and see that it is boyfriends and girlfriends, husbands and wives, that it is couples going around, or girlfriends travelling around that there is obviously this very broad appeal," Patten said.
Another sign of the adult entertainment industry's shift to the mainstream is the businesses willing to get into bed with Sexpo.
Exhibitors include the predictable sex toy, lingerie and pornography sellers but there are also people promoting jacuzzis, sports cars, exercise equipment, remote-controlled helicopters and music merchandise.
Sexpo is on at Sydney's Hordern Pavilion until Sunday.