I look back with bemusement at the moment I had to pull a friend aside from a conversation about oral sex, to ask desperately, “Kate, what’s a blowjob?” She shrugged, admitting she had no idea either.

I was 12. I thought Kate and I were simply too naive to aspire to the heights of sexual maturity to which the boys had risen.

Their wisdom seemed self-evident – they did, after all, studiously compare notes on the hottest porn star on RedTube, and congratulate one another on the previous night’s masturbation.

It only occurred to me recently, at the still tender age of 20, that these boys had no idea what they were talking about. Yes, they could name dazzlingly complex sex positions such as the “backward upside down cowgirl” that I thought only a contortionist could achieve. But, really, they were just pontificating on the basis of a few illegally downloaded porn films, traded around on memory sticks at break time.

Only a year before, they had been trading Pokémon cards.

My first lessons about sex didn’t come from sex education lessons, but were filtered through pre-pubescent boys, who received their information from porn. A 2008 report into youth exposure to pornography, carried out in the US, found that from a pool of 5,000 undergraduate students, 93% of boys and 62% of girls had been exposed to internet porn before the age of 18. The report also found that “boys were significantly more likely to view online pornography more often and to view more types of images”.

Porn provides a huge bank of sexual imagery, at the click of a button. Regrettably, it often depicts aggressive sexual acts – a 2010 analysis of 50 bestselling adult videos in the US found that 88% of the scenes included physical aggression. This aggression is overwhelmingly carried out by the male, with the target of the violence being a woman 94% of the time. In addition, porn rarely depicts romantic intimacy, tending to omit kissing, verbal compliments or laughter.

Sex is now referred to, among other things, as “beating” and “boning”. These brutal terms reflect the depiction of sex in pornography, with its archetypes of the dominant male and submissive female.

ChildLine reports receiving calls from young people every day, worried about how unlimited access to online pornography is influencing their perceptions of sex. One young teenage boy told them: “I’m always watching porn and some of it is quite aggressive. I didn’t think it was affecting me at first but I’ve started to view girls a bit differently recently and it’s making me worried.”

I think that boy had a point. While watching popular porn films, depicting scenes of sexual violence, people unwittingly normalise that behaviour.

Porn depicts sex without responsibility, in a way that is both acceptable and alluring.

I learned this the hard way, as the young women I knew would be rated out of 10 for “fuckability”. I learned this, too, when I was coerced into having sex with someone I was scared of. I learned this when I saw some of the degrading acts regularly played out in porn films replicated in bed.

Sadly, I also learned to be scared of sex.

The porn industry currently has far too big a role in sex education, and it starts influencing boys and girls at a difficult age. It tends to start filtering into the conversation around sex at an age when both girls and boys have heightened body image issues, when they are under great pressure to conform socially and don’t necessarily have the experience or confidence to demand their sexual rights.

Adults are supposed to guide young people to make sound sexual decisions. But in February, the education minister, Nicky Morgan, rejected calls for sex education to be made statutory both in primary and secondary schools, despite receiving a joint letter from the chairs of the education, health, home affairs and business committees, calling for sex education that can “help protect young people from abuse in many forms”.

Even when sex education is provided at school, it is often farcical. In my experience, SRE (sex and relationship education), was always taught within the framework of either risk or biology. “Beware of STDs, children – and your life will be totally ruined if you get pregnant,” our teacher would lecture a room full of bored 14-year-olds. She would only arouse the interest of the class when she pulled a “wooden willy” out of her bag. At this, the class would shriek with excitement and start filling condoms with water and throwing them at each other.

This is hardly an environment conducive to learning, which hasn’t gone unnoticed by students, 40% of whom say the SRE they received was either “poor” or “very poor”.

Trying to engage young people in conversations about sex can be difficult, and there’s sometimes a tendency for people in authority to ignore the reality of teenage sex, or advocate an unrealistic policy of abstinence.

Students at many UK universities are now setting up consent classes, and it would be good to see these messages form the heart of SRE in schools. These classes teach students that they have autonomy over their own bodies, and that sex should involve the enthusiastic consent of both parties. Such messages need to be instilled before students leave school, since the average teen loses their virginity at the age of 16.

SRE also needs to include discussion of porn, and its potential to influence one’s conception of sex and relationships in a negative way. So far, attempts to mitigate the negative effects of pornography have tended to revolve around the idea of blocking young people’s access to it. But internet blocks are not effective barriers to accessing porn, and they also introduce an unhelpful element of shame. Instead of advocating abstinence – regarding sex or porn – teachers should accept that it is natural to be curious.

It would be better to encourage critical thinking about pornography, and to discuss how porn might contrast with real sex – to ask why pornography never depicts participants checking how the other is feeling, or asking for their consent.

I had a very honest conversation with my mum about some of my early sexual experiences, and her response was one of sadness, but not surprise. With only my lousy SRE lessons to help me, I was unable to understand my feelings of discomfort and shame after feeling obliged to have sex. More importantly, I wasn’t equipped with the confidence to say no.