This is a piece about how pornography is like a plastic bag. It is also a piece about the fact that I watch pornography. The first of these statements may seem surprising. The second absolutely should not.

More precisely: to make the second statement may be relatively unusual. But if I gave you my particulars – 29 years old, male, with a reliable internet connection and a working knowledge, gleaned as a teenager, of my browser's "delete history" facility – you could have guessed the underlying detail with a high degree of confidence. I suppose it's possible that I'm an outlier, exposing myself as a total creep by saying this, but I don't think so.

We know that men watching pornography at least occasionally is an absolute given among my peers, who are, I like to think, at the relatively well-adjusted end of the spectrum. In the course of writing this piece I've checked with at least 10 of them, and they all agreed that the same could be said about their friends outside of my own circle. (Sorry, guys.) A Twitter and Facebook trawl of about 45,000 people also turned up a vanishingly small number of men – six – who never watched porn. The tone of several exchanges I had on the subject made it clear that those few conceived of their habits as being in sharp opposition to the mainstream.

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These are frustratingly unscientific methods of assessment, partly enforced by the relative paucity of data on the subject, itself the consequence of our embarrassment. Still, there are some pointers available. On Friday, a traffic analysis found that British people click on porn sites more than they do on social networks. A 2008 study found that 86 per cent of young adult men watch porn, 69 per cent at least once a month. And when, a year later, the University of Montreal tried to conduct a study into the views of men who never watched porn, it failed to find a single candidate.

The truth is, even the necessity of doing this sort of groundwork feels a little ridiculous. It seems to me uncontroversial to say, as an absolute minimum, that it is not unusual for men to watch porn. If you were feeling just a little bolder you could surmise that, in fact, a significant majority of men watch porn; that quite a lot of women do, too; and that, among young adults, exposure is nearly universal.

Now the Government is trying to catch up. Last week, David Cameron announced that the major internet service providers had agreed to the introduction of "default-on" porn filters. The months-long debate leading up to that step has felt like a significant moment in the collective understanding of how profoundly our relationship with pornography has changed since high-speed internet became the norm. Apparently, a lot of people who grew up having no option but grot mags at the newsagent have had a nasty shock. They are only now discovering, mostly second-hand or by searching for "sex video internet" on Google, just how accessible, varied and repugnant this stuff can be.

And yet, many speeches and gallons of ink later, we don't seem to have got very much further than the principles that children shouldn't see pornography, and no one should see images of child abuse. We can't even agree on whose responsibility it is to enforce these axioms, on whether it's technically possible, or on whether The Sun should be subjected to the same rules as YouPorn. We certainly haven't managed a mature conversation about what sort of moral framework we want to apply to pornography. To me, the explanation for this seems obvious. Everyone is willing to say: pornography is everywhere. Almost no one is willing to say: and I have seen some of it.

So, um, yes. I have seen some of it. I don't say so with any sense of pride. Also, in the interests of preserving at least a wisp of dignity, I should like to add that it's not, y'know, a hobby. Even so, I guess I know more about it than most of the wide-eyed ingénues who have formed such strong opinions about its impact of late. This is why it seems worth mentioning. In most areas of controversy, the views of the ignorant are at least occasionally balanced by plaintive corrections from the better-informed; in this one, the ignorant, or pseudo-ignorant, have the field almost unopposed. With a very few exceptions (such as the New Statesman's Laurie Penny), no one says, well, you haven't got that quite right, because to do so reveals greater familiarity than we are generally willing to admit.

That squeamishness about detail isn't merely a matter of sociological interest. It has real consequences. It means that the argument about pornography becomes binary: on or off, consensual or exploitative, arousing or repellent. And then, because most of us are instinctively opposed to censorship, we sigh that it's a fact of life, and we just have to put up with all of it. Consider Cameron's speech last week, which featured, among the easy (and, it turned out, ill-considered) applause lines about child protection, only one moment of engagement with the granular detail of porn, in his vow that depictions of rape would be banned – as if there were anything bold or controversial about the idea that videos which normalise so reprehensible a crime should be beyond the pale.

Because he is a politician, and has therefore never seen any pornography ever at all ever, that's about as far as Cameron can go. Probably that's for the best: the really important debates about pornography should not be about legal principles, but ethical ones. Here's where my – oh, God, there's no other word for it – expertise comes in. I can tell you, for example, that if you're interested in watching two people having sex (and see no moral problem in that interest) but not so interested in watching women being treated badly, your options are pretty limited. I can tell you that it is quite common to have 18-year-old girls dressed up in school uniform and filmed in a classroom. I can tell you that condoms are rarely sighted, and that performers in the US – who will simply not get work if they insist on them being used – have contracted serious illnesses as a result.

There is lots more of this detail, but it only gets more specific, and you probably don't want to read about it over your breakfast. Still, it's enormously important. A few years ago, I interviewed The Sun's agony aunt Deidre Sanders, who told me that the biggest change in the make-up of her postbag since she took up the role in 1980 was the precipitous growth in letters from men and women whose relationships had been affected by pornography. I feel pretty confident that I have always been able to keep fantasy and reality distinct, but there will certainly be some people for whom that is not true, and, even if these default-on porn filters delay children's exposure a little, there will certainly be more of them in future. One study found that 90 per cent of content on the most popular porn sites featured physical or verbal abuse against women, and you don't have to be Mary Whitehouse to find that concerning. We need to do something about it, and since we are not going to outlaw pornography altogether, we need to figure out what that might be.

Here's one suggestion. In my own consumption of porn, I have always tried to avoid those tropes that I find unsettling. But in the writing of this piece, I have realised that I am not careful enough. I avoid the misogynist video, but I may be careless about avoiding the site that hosts it; I feel bad about the unprotected sex, but I don't bother going to the great lengths it would require to find the alternative. I am really ashamed about this, and I'm going to take a great deal more care in future. The source of my shame, straightforwardly enough, is not some new-found moral clarity, but the fact that you are now reading this, and so my behaviour has been exposed. For me, at least, the use of pornography has become a semi-public fact.

In isolation, this doesn't mean very much, except that everyone I know is going to laugh at me for a while. More widely, it might mean quite a lot. What if we ditched the stigma carried by pornography in general, and instead attached it, loudly, to the pornography that we consider to be unacceptable? We have seen this principle applied in so many other areas. People are, basically, too lazy to make ethical choices. The only way to get us to do so is to incentivise us with a little bit of shame.

Think of battery farms, of sweat-shop clothes, of – yes – the fight against plastic bags. Pornography is not immune from the behavioural economics that shifted all those battles. If enough people said they sometimes watched porn, and also said that they hated the misogyny that accompanies it, some entrepreneurial spirit would surely intervene. And if there was a porn site that promised me I could surf it without any risk of coming across anything I needed to worry about (there are some out there, but none has reached critical mass), I would visit it exclusively, with enormous gratitude to its creators for taking the effort out of doing the right thing.

It is, I suppose, a call for a wanker's code: a contention that being interested in sex is not the same thing as being interested in violent misogyny, and an appeal for a proper conversation about splitting the one off from the other. Because, yes, we are wankers. But that doesn't mean we have to be shitheads.