When Leah Holroyd joined a dating site five years ago, the 31-year-old noticed a lot of men had listed The Great Gatsby as a favourite book. “So, to be slightly provocative, I mentioned in my profile that I thought it was overrated, and challenged someone to persuade me it was great,” she says. A postgraduate student in English literature sent her a message that read “a bit like literary criticism”, and they began exchanging messages and discussing their favourite books. Holroyd found him pleasant enough, but she was looking for a relationship rather than just friendship, and he only ever talked to her about authors.

After a couple of weeks, the bibliophile said he would be visiting London where Holroyd, who builds online learning courses, was living. “He asked if I fancied meeting for coffee and a walk by the river,” she says. He suggested they swap phone numbers to make arrangements easier. “Almost instantly, he sent me closeups of his penis.”

If the conversation had some potential, but was becoming boring, I would sometimes send a dick pic

Holroyd’s experience is worryingly common. A 2018 YouGov poll found that, shockingly, four in 10 women aged between 18 and 36 have been sent a photograph of a penis without having asked for one – colloquially known as an unsolicited “dick pic”. (Only 5% of men in this age group admitted to having sent one.) Nor does this just happen through online dating. Some men have used the AirDrop function on their Apple devices – which allows users to share files with other nearby Apple devices – to send unsolicited pictures to women. Anyone, of any age, who has AirDrop turned on at its most unrestricted setting is at risk of picking up their phone to see a graphic image that was sent anonymously by someone in the same restaurant, cinema or train carriage. The problem has become widespread enough that MPs and campaigners are now calling for a law targeting “cyberflashers”.

Laura Thompson, a researcher at City, University of London, whose work examines harassment over dating apps, says the issue has until now been trivialised. “The research in this area is really limited. I think this blind spot says something about how society and the law tends to think of the problem: that dick pics are an annoying internet phenomenon as opposed to ‘real’ flashing. The term ‘cyberflashing’ wasn’t even in widespread use until about a year or so ago. Research reflects the world we live in, and I just don’t think this problem has been taken seriously until relatively recently.”

Yet the question that plagued me after hearing Holroyd’s story was: why? What happened in the mind of that man between talking about books, inviting a woman for coffee and a walk – and sending her a photograph of his penis? Unsurprisingly, I did not get very far by asking men in person if they had ever sent unsolicited photographs of their penis. So I set up an account on Reddit, where users can post anonymously in forums on a range of topics, and I asked the question again. Shortly afterwards, I went to the cinema. When I checked back a few hours later, I discovered more than 500 comments, and the moderators had shut the thread down.

The comments were fascinating. The most important thing I learned is that sending pictures of one’s genitals has different meanings for different men – and different meanings for the same men at different points in their lives. Stephen Blumenthal, a consultant clinical psychologist and psychoanalyst at the Portman – an NHS clinic that offers specialist long-term therapy to patients with disturbing sexual behaviours – says: “There’s always a tendency with these issues to provide one kind of formulation; a one-size-fits-all explanation. But the reality is that there are many different motives that people have, some of which are perhaps more troubled and troubling than others.”

Illustration: Guardian Design

Some who shared their experiences anonymously wrote about not feeling confident with their bodies, and wanting praise. One Reddit user, Jake, told me: “I’ve done it a few times in the past, and I think it’s mostly about validation. Although most men will never admit to it, we are very insecure about our bodies, especially down there. So, unconsciously, we just want someone to say we look nice, or that we are attractive. OK, sending an unsolicited dick pic is really not the way to do it, but I do think that’s the driver. We are just desperate for someone to tell us we’re OK. Not even sexy or incredibly handsome – just OK.”

Others described wanting to turn up the sexual excitement in a messaging conversation they felt was flagging. Another user, Dave, wrote: “If the conversation had some potential, but was slowing down or becoming boring, I would sometimes send a dick pic. Because either they stop texting me or I get laid.” He added that “dick pics now only get sent upon request”.

For others, it was “a numbers game”. For all the unsolicited pictures that were ignored or rebuffed, there was the occasional woman who responded in kind, and if one picture “worked”, it was worth it. Jake wrote: “When they were well-received, I felt good about it, from the validation and the boost to my self-image, but also the precedent it opened. It was now OK for them to reply in kind, or to steer the conversation down more sexual routes.”

Another, John, estimated he has sent 100 unsolicited pictures in chatrooms over the years, after becoming aroused. “I’d see people chatting about various subjects. If they were remotely sexual, I think that served as my entry point to sending a pic,” he wrote. While he did have a couple of his “best pictures” saved on his phone, “the thrill of it was taking a pic in that moment and sending it … I think it may have been about creating or imagining some kind of sexual connection in that moment. The feeling was a bit of a rush in the anticipation of a response.”

He described the four types of responses he received: very rarely, it would lead to an overtly sexual conversation in a chat window, in which further pictures might be exchanged; or he might be sent a complimentary message; or he might receive a negative, angry response. But, most often, he received no response.

John is now in his 60s and has not sent a picture like this in more than a decade. He wrote: “As I have become older, frankly, it just seems a combination of rude, silly and empty. I have learned this is offensive and an unwanted intrusion, even if it is the internet and anonymous. Even online, it is a violation, in my opinion; little different from the stereotypical street flasher in a trenchcoat. Really, those who send these unsolicited pics are essentially standing on a virtual street corner digitally flashing women they don’t know for their own sexual gratification.”

I was intrigued by John’s condemnation, so I asked if he included himself among these online flashers. “Yes. The anonymity of the internet facilitates doing things online you’d never contemplate in the real world, so I think that helps men distance themselves from any consequences or impact on the person they send it to.”

The guy on the train using AirDrop is looking for something very particular … he wants to see shock and surprise

This notion makes a lot of sense to Blumenthal. “The internet has brought out all sorts of new varieties of unusual sexual proclivities that are related to previous versions, and might have some similar dynamics,” he says. Blumenthal believes there is a hidden narrative underneath some of these stories, which is what he has experienced with his patients who have committed indecent exposure: “Some will be trying to impress, whereas some will be seeking to intrude. And this intrusive aspect is an important one,” he says.

“The guy on the train using AirDrop is flashing in the digital age. The flasher is looking for something very particular: he is interested in the response, focused on the faces of these women – he wants to see shock and surprise, and a kind of disabling of the person he is flashing.”

In almost every case of real-world indecent exposure, he says, there will have been a childhood incident where the perpetrator endured a trauma that made him feel out of control. This is the notion of identification of the aggressor: determined never to be a victim again. As an adult, he unconsciously twists this act around so that, “he is now in the driving seat, watching the reaction of those he disturbs, inserting into his victim a feeling of shock, surprise, disturbance”.

John says he has never heard about women being distressed by pictures sent by somebody they are already talking to online, describing them as “really more of an annoyance”. Perhaps some women do feel that, but others find them much more disturbing. When Holroyd received several explicit pictures from the man with whom she had just agreed to go for coffee and a walk, she tells me, “I felt totally shocked. Nothing in the conversation had made me think he was going to do that. I felt really worried because it seemed like a deception, I was confused, I didn’t know what he was really looking for, I didn’t feel safe.”

When she replied to this man to say that she no longer wanted to meet him, she says, “he got really angry and aggressive. He told me that I must be mentally unstable because I had changed my mind so quickly. He said: ‘If you can just change your mind like that there’s something wrong with you.’ And he told me I should get professional help. He put the blame on me; made me feel I had done something wrong and had been unfair to him.”

In expressing his rage towards Holroyd, he was also describing exactly how he had made Holroyd feel about him: he was the one whose behaviour had been unstable, unpredictable, disturbed and disturbing. He had projected his feelings directly on to her.

There were many thoughtful and thought-provoking responses to my question on Reddit. But in response to the many posts from men insisting that some women like receiving them, one woman replied: “If a woman wants dick pics, it’s easy to ask for them. Or for a man to ask a woman if she would like to receive one. This [sending unsolicited images] is just like pulling your dick out in front of someone – of course, loads of people are into that, but you need to make sure of that before you do it, not just shrug and say: ‘Eh, some women would have loved it!’”

Some men said they had stopped sending unsolicited photographs after a negative response. Another Reddit user, Jeremy, wrote about the one occasion he sent a photograph to a girl he had been messaging on Tinder: “She replied with: ‘Ew!’ and blocked me. Rightly so. Haven’t done it since.”

Others replied that leaving it up to women to teach men what is acceptable by responding negatively could put those women at risk.

Blumenthal says that it is crucial to distinguish between noncontact offences, in which the perpetrator does not touch his or her victim, and contact offences – and that the overlap between those who commit indecent exposure and those who go on to sexually assault their victims, is low. Yet the term “noncontact offence” in this context, is an interesting one – it almost feels inaccurate: while sending an unsolicited photograph does not involve physical contact, it can feel like a violation; an assault.

Cyberflashing can be prosecuted under a number of different laws, which carry prison sentences of up to two years. But there are problems with these laws, says barrister Kate Parker, director of the UK-based Schools Consent Project, a charity she founded to educate young people about consent and sexual assault. A prosecution would need to prove that the sender’s purpose was either to cause distress or anxiety, or that the image was “grossly offensive or of an indecent, obscene or menacing character”.

Parker says: “In an era where sending dick pics is becoming increasingly normalised, the depressing reality is that such intent might not be proven. Some men think it is an appropriate way to start a conversation, or take an existing conversation to a more ‘flirty’ level.” And when it comes to the notion of indecency, the threshold is increasingly high: “as our online and offline worlds are increasingly saturated with sexual imagery, it may be that society’s collective perception of sexual indecency begins to shift”. She supports the creation of a new law – one “that finally includes a consideration of the recipient’s – typically a woman – response to such messages as a determinant of criminal liability”.

We can improve the law, criminalising this latest incarnation of flashing, but, unless we try to understand the motivations behind it, we have no hope of stopping it. When I was a schoolgirl, a man flashed me as I walked home from the local park – he ran ahead of me then stood masturbating, with his T-shirt over his face. When I was 17, on holiday in Paris with my best friend, a man thrust a photograph of a deformed penis in our faces. When I was in my 20s, a man I was flirting with texted me an unexpected dick pic. All these experiences, shifting in format, but not in nature, as technology progressed, were shocking, and unpleasant. On the upside, I am happy to report that in researching this piece, I did not receive a single one.

Some names have been changed. For help and advice with any of the issues raised in this article, go to schoolsconsentproject.com