It felt as though I was walking through a live re-enactment of 50 Shades Of Grey. While one woman dripped candle wax over her naked breasts as a couple looked on, another, dressed head-to-toe in PVC with a long black braid, cracked her whip and led spectators through rooms containing various eye-popping paraphernalia.

Welcome to a high-end sex party, where couples get to explore their hedonistic side, as far away as possible from the humdrum school runs and grocery shops of their daily lives.

Run by Kate Middleton’s former school friend Emma Sayle, Killing Kittens - the infamous organiser of such events - was founded in 2005, apparently in response to a growing demand for female-focused events from young, single women.

But, two decades on, amid the soaring use of dating apps and online pornography, and with polyamory increasingly seen in the mainstream, who actually feels the need to attend parties like these?

I donned a Venetian mask and an evening dress to find out. And the first thing that struck me was that guests certainly weren’t confined to the young - or indeed the single.

Rather than beautiful, young things cavorting around the grand stately home, I found middle-aged couples intent on reigniting the spark in their marriage. I had assumed I’d be one of a number of twenty-somethings, but it was all middle-aged mums and dads. At 25, I must have been the youngest by at least 15 years.

Never having thought of myself as a prude, I suddenly felt like an ingénue compared to all these seasoned sex-partygoers.

Killing Kittens events claim to ensure female sexual pleasure is the priority. The policy of ‘Kittens first’ means only women are allowed to make the first move. In fact, single men are banned, with men only admitted if they’re in a couple with a woman.

Poppy wore a Venetian mask and an evening dress to the sex party, held at a sprawling Victorian mansion in Berkshire with extensive parklands and a snaking gravel driveway

To apply for tickets, you must be female, over 21 and a member of the ‘Kittens Association’. To acquire membership you have to go through a vetting process that itself costs £50.

Once accepted, you can buy tickets (normally £200) to various monthly parties held at secret locations across the UK and Europe.

This particular event took place at a sprawling Victorian mansion in Berkshire with extensive parklands and a snaking gravel driveway. Upon arrival I was shown to a darkened parlour, where I waited with the other bemasked early birds.

Glass of complimentary prosecco in hand, I watched as women wandered in wearing long evening dresses with plunging necklines, thigh-high splits and cut-outs designed to pique the interest of fellow Kittens - and Tom cats. The male guests wore black tie.

At 8.30pm, we were ushered into the grand, panelled hall, where seductive music played and every available surface was covered with flickering candles.

In the gallery overlooking the terrace and formal gardens, bartenders twirled bottles and flipped glasses, while guests perched on bar stools around little tables or sank into high-backed velvet sofas and armchairs.

Boxes of luxury dark chocolate infused with ‘aphrodisiac’ ingredients littered the high tables, and as I was nibbling on a square of delicious rose gold chocolate, a couple came over and asked if they could sit down. Expecting a chat-up line, I braced myself - only to have the woman merely explain that her stilettos were already hurting her.

The man, who seemed to be in his 50s, shyly smiled at me from behind his mask, while his forty-something fiancée launched into conversation. They had been together three years, having first met at work, and had got engaged in Mauritius last summer.

When I asked how they had got into sex parties, the woman said she’d always been curious but it took a while for her to broach the subject with her partner - and even longer for them to dare to attend one.

When they did, it was a bit of a bumpy start; while he loved it, she hated it, feeling awkward and overwhelmed. The second time their reactions were reversed.

Now, though, being well-versed in the etiquette of such an event, they seemed excited for what the evening might bring. They made their excuses and headed to the bar.

At 10.30pm, I noticed a queue had formed in the hallway snaking away from a small cloakroom, where excited Kittens were now swapping their evening dresses for sheer bodysuits, crotchless panties, nipple tassels and more. The men, in contrast, stripped down to their boxers and patterned socks, typically with stiff white shirts undone to the navel.

Soon couples headed off into the plush, decadent bedrooms known as ‘play rooms’ - and I eagerly followed, excited to see what was on offer.

At the top of the grand wooden staircase, a huge sign explained the rules: no men allowed in the play rooms on their own, and consent at every stage is key.

The largest room contained three huge beds draped in black bedsheets, which were already occupied by writhing naked bodies. Couples having sex quickly gave way to groups of six or more climbing on top of each other.

I wandered down a corridor lined by similar, smaller rooms full of couples moaning and groaning.

Politeness was the order of the day. ‘May I touch your breasts?’; ‘Can I remove your panties?’; ‘Mind if I join in?’ echoed around the rooms.

Inside a dedicated BDSM chamber, one couple were making full use of the props available - the man stood spread-eagled and tied to four corners of a large X while he was spanked by a woman wearing only towering stilettos.

Another woman was strapped into a sex swing, her companion dressed in a leather harness. I left the room feeling excited but shocked at their exhibitionism.

One woman asked me if I’d happened to see her underwear. I shook my head.

‘Always wrap your knickers around your wrist - that’s my advice,’ she said as she continued to scrabble around the floor in search of them.

Still fully clothed, I felt out of place among all the naked bodies. I didn’t know where to look - to make eye contact seemed to invite a dalliance but to avoid looking altogether felt prudish.

Kate Middleton’s former school friend Emma Sayle founded Killing Kittens - the infamous organiser of these sex parties - in 2005, apparently in response to a growing demand for female-focused events from young, single women

In one room, women performed their own impromptu erotic dances. One man simply followed his partner as she strutted around the room, lightly slapping her bottom.

While the event was billed as a space primarily for women’s pleasure, I couldn’t help but feel all the posturing by the Kittens, the lacy lingerie and the porn-style moaning, was more for the sexual gratification of the men they’d brought along.

I made my way back downstairs to the parlour, which was now full of entwined naked couples.

The couple I’d chatted to earlier bounded up to me breathlessly, him in his boxers, her in a sheer bodysuit. She asked me how I’d found my evening, with a twinkle in her eye, and I replied it had been extravagant and fun.

By now it was midnight, and I’d had my fill of this boundaryless hedonism. When the couple eagerly suggested that this didn’t have to be the end of my night, I was glad of the excuse that my taxi had arrived.

The man persisted, suggesting I join them for a menage-a-trois the next morning in the ‘excellent’ steam room in the hotel we were all staying in. But I told them that sadly my early check-out would prevent that.

In truth, I was only too happy to get back to my very vanilla daily life.

Had I been turned on? Yes. But it turns out group sex isn’t for me. And I’d witnessed enough sexual proclivities to last a lifetime.