"Some nights get a little more full-on than others," the club's founder warned me.
"Because tonight is rope bondage, and we advised members bring a partner, it might get more sexy."
It won't surprise you to learn that sex clubs abound in New York City, where I've lived and worked as a writer and editor for the past two years since leaving Australia. A little more unexpected, though, is the clientele you will spot at these events; lawyers, entrepreneurs, CEOs, models, writers, and the finance guys and girls from Wall Street - all of them young, all of them attractive.
This crowd is flocking to a new elite, membership-only club called NSFW (Not Safe For Work) that's ridding the "sex club" of its unsavoury stigma and attracting beautiful, successful millennials desperate to not only take part in its envelope-pushing events, but pay for the privilege.
"Most of our members are around 27, so youth is an important factor for us," NSFW's founder, a successful New York businessman who operates anonymously, told me at a recent rope bondage class.
To assess whether you're the right fit he and his team analyse your social media feed and comb through your friends list - oh, and you have to be hot, naturally.
"Members tend to be physically fit and we require [applicants] submit profile links to review before accepting membership. We look through their feeds, see what kind of friends they have, where they travel or party, and what type of things they post," he said.
Membership is $6.66 per month, and only after making it through the thorough screening process - and about a one-month waiting period - are you allowed to join. Since NSFW launched in January 250 members have been approved, with nearly 500 hanging out to get on the wait list.
Additional payments of anywhere from $20 to $250 are due should you RSVP to an event - on Tuesday you could be invited to a class about BDSM, Wednesday could be a seminar about sex and consent, and Saturday night might be a three-floor dance party with live entertainment and designated shared rooms for sex.
As a first-time sex partygoer, I was hesitant before my first event - what exactly will I have to do here? - but the NSFW team assured me that not everyone gets hot and heavy, and it's certainly not an expectation - however yes, sometimes couples get, uh, physical.
Members must practice what NSFW dubs "enthusiastic consent," so that no one feels uncomfortable or pressured. One female member I spoke with ahead of the party even told me that this strictly-enforced rule means she feels safer approaching guys - or being approached by them - at NSFW event than she would at a regular club.
So, it was armed with all of this information - and a heavy dose of curiosity - that I checked my judge-y preconceptions at the door and agreed to attend one of the club's buzziest classes; a rope bondage event led by a dominatrix named Goddess Aviva.
I arrived at the trendy apartment in Manhattan's Lower East Side at around 9.30pm, was handed a small glass of red wine and introduced to a couple of members. Scanning the low-lit room, I noticed it was decorated with cozy floor cushions and lounge chairs, and a long table was set up with ropes. A modern, suggestive video played on a projector against one wall.
"We'll sit on the lounges or the chairs with a partner while Goddess Aviva leads the class," an NSFW co-ordinator told me.
After about 30 minutes and just one glass of wine to combat my nerves - this rookie was not getting kicked out of her first sex party for being tipsy - I joined about 15 beautiful couples on the couches.
A few giggled as Goddess Aviva handed out the ropes and introduced her partner for the demonstration, an attractive woman kitted out in leather and lace lingerie.
"This is much easier if you have less clothing on," she hinted, as the women around me and some of the guys in the same-sex couples took that as the cue and stripped down to their underwear. Even less for some.
"Hellllll no," I thought, self-consciously zipping my leather jacket a little higher.
I seemed to be the only one feeling even slightly uncomfortable.
While only a few people in the class were well-versed in bondage, couples either laughed confidently as they tried and failed to turn ropes into body harnesses, or kissed intimately, sitting on each other's laps, nearly nude and seemingly oblivious to the room full of strangers sitting around them.
So, what's the actual appeal for 20-and-30-somethings clamouring for membership? At the end of the seminar, having learned how to tie someone safely (no rope burn!) to a bed post and make a nifty body harness, one NSFW veteran told me the events were simply amazing networking opportunities, and another said he often took dates to the parties.
It's more memorable than dinner and a movie, I suppose.
Oh, but guys, please check first before taking your Tinder date to a sex party. It's not everyone's cup of tea, trust me.