Two days before NKD – a nudist festival for 18 to 35-year-olds in Dorset – I was warned by organisers British Naturism that clothed journalists hadn't gone down too well in previous years.

"If you want to come and write about the festival," they said, "you'll have to do it naked."

I wanted to find out what's attracting young Brits to something we in the UK overwhelmingly associate with German pensioners, so I agreed, despite the fact I still involuntarily shudder whenever I remember the time – two years ago – that I accidentally flashed a hotel receptionist my boobs.

I shouldn't worry, a friend had said; taking my clothes off in front of a load of strangers would be like "ripping off a plaster". She was right: it was painful, and it was quick – so quick that I barely had the chance to google whether you're supposed to put suncream on your vagina before I was unleashed into a field booming with 170 sets of bare genitalia.

Before I could ask any questions, and find out what I was there to find out, I had a morning activity to take part in: a nude exercise class. I didn't particularly like the sound of it, but it did act as a convenient excuse to escape the 30-year-old man from London who was trying to convince me to cancel my train home that evening and camp out for the night. So I squatted, planked, star-jumped and ran through a field holding hands with a few dozen men while everyone else watched.

Nudity aside, the vibe wasn't really what I'd expected from a field full of nudist millennials. When my friends and I spend the day in a park, we talk, but we also instantly take any lull in conversation as an opportunity to check our phones. There was none of that here – which might have had as much to do with the lack of pockets as the fact that some guests were there to reject technology and social media, if only for the weekend.

The other reasons I was given for attendees' interest in naturism ranged from the prosaic – it was "just easier to go to the beach naked" – to the personal, in particular that it was a confidence booster. A 24-year-old carer wanted to try nudism because his job made him realise nudity was nothing to fear, and that made him feel better about his body.

According to research by the Journal of Happiness Studies, the boost nudism gives our body confidence comes from seeing others naked, not so much from being naked ourselves. There weren't many women receiving this extra shot of spirit at NKD, because there weren't that many women there – the few I saw were with male partners. According to everyone I asked at the festival, women are often vastly outnumbered by men at nudist events.

If you're thinking that out-of-whack ratio can lead to some creeping, you'd be right. My radar went off a few times at NKD, including the moment a man insisted on applying sun cream to my back and I was too distracted trying to prioritise which body parts to cover with a blanket to fend him off. That said, the vibe was generally very non-sexual – as is pretty much always the case at nudist events.

"Nudity becomes desexualised because people here are doing very normal things," said 28-year-old Dave. In fact, he elaborated, he finds nudist women less attractive than women wearing clothes.

The gender imbalance isn't British Naturism's only problem; there's also the diversity issue. One study measuring body confidence of people going to two naturist events – including one organised by British Naturism – comprised of 831 white people, four Asian people and zero black people.

"This is a very white event – we need diversity," one guest told me.

While it seems that as many young adults as ever are stripping off for skinny dips, naked dining and bike rides, NKD visitors told me that young people are shunning the traditional membership organisations that have kept older nudists in the game. British Naturism doesn't have figures on how many young members they have. The number is rising, they say, but young people still make up a small portion of their membership.

"There's a group of young people here who told me they're naturists because their parents are. The tough nuts to crack are young people like me who weren't brought up that way," said Dave.

The labels of "naturist" and "nudist" also aren't too popular among this younger generation of naked people. Among one group I spoke to, only half said they've told friends and family that they're naturists. "I just told the office I was going camping for the weekend," said Dave. "I don't want to be labelled a naturist – I can barely be naked in my own home; I don't want to be known by my neighbours as 'the naked guy'."

Some told me they didn't want people to associate them with any perceived negative assumptions about naturism. "Even though you know nudists are a normal mix of people, I worry what assumptions people would have, because all they know of naturists is what they see in movies, where they're used for comedic purposes," said 40-year-old Will.

That certainly is a misrepresentation, because my day was largely spent in a humour vacuum. While people were chatty and personable, the whole thing felt a little sombre. One guest told me he didn't want to be known as the guy who gets naked all the time, but that he'd rather be known "for his work". I asked him what his work was; he replied, "I'm a statistician." Naturists – they're just as dull as the rest of us!

There's nothing illegal about being naked in your back garden, so why pay to go to a festival to sit around in the buff there? No one could give me a compelling answer – but in fairness, maybe it isn't that deep.

As far as I could tell, this was just another opportunity for people to come together in increasingly isolated times, in search of connection. A lot of men were there on their own, presumably because they're lacking that connection in their clothed lives, despite one lone man conceding that he often finds he has little more in common with other nudists than a mutual disdain for clothes.

The people at NKD stood apart from other millennials for more than their full-frontal rejection of social norms. They were friendly, but generally they were also shy, serious and a little awkward. I got the feeling that some of them were looking for something more than shared nudity; that they felt like outsiders to the clothed world for reasons other than clothes.

And after spending the day counting down the hours until I could leave a world that made me feel uncomfortable, I started to understand the lengths that these NKD attendees have to go to to do the same.