As a report says early access to extreme online pornography can leave children with a distorted view of sex, one woman talks candidly and explicitly about how it made her think rape was normal.
When Karen (not her real name) was 16, she got into her first relationship with a boy who was keen on watching online pornography.
He even had a smartphone he kept secret from his parents, which he used solely to view pornographic material.
"I thought because I had grown up with guys always watching it and with my girlfriends watching it as well, I just thought it was normal.
"That's just what everyone does," she says.
She saw pornography for the first time at the age of 11, in the bedroom of a friend's older brother, she says.
After that, pornography became part of her social landscape, with links to favoured sites and films shared between friends like music videos.
"It was just an average thing - there weren't any alarm bells ringing or anything."
But then things got darker.
"It wasn't until we started to get intimate that I realised the extent to which he watched it, and the type of things he watched - that it wasn't quite the same as what everybody else was watching.
"He used to like us watching porn while we had sex," she says. "And it was during those times that I realised the type of thing that he was watching was very graphic, very hard-core."
And as the relationship progressed, they began watching what she described as "rape porn" through a smartphone propped up on the pillow.
"He used to re-enact what he saw on the screen with me," she adds.
She says she felt expected to perform the role of the woman even though effectively, she was being raped.
"He was my first boyfriend, and I thought this is what a sex life was, this is what I have to do."
But even though she was not enjoying what was happening to her, she says she did not feel, as a 16-year-old girl in her first relationship, that she had a right to say no.
"I thought what was happening in the videos was normal as well, because he had made me watch so many of them.
"I thought if I am not enjoying it, I am not doing it right, and I didn't feel that I was ever able to say no."
And she is clear that some of the videos she was obliged to watch appeared to be "real rape".
"Those women were obviously highly distressed, and crying and screaming.
"And at times that would be the state that I was in and, I think he thought, I was playing that role again, and I don't know if he realised that those women were not acting and I wasn't acting."
Karen says she was genuinely "terrified" at these times, and that she just wanted it to finish and for him to go off and make her a cup of tea and to be the "nice boyfriend" he could be.
Her view of sex and sexuality appears to have been shaped by the pornography that she watched.
She felt as if her own needs and desires were unimportant and that it was her role to please her man.
"No-one talks about female sexuality," she says.
"It's all about what the man wants and their lusts. Women parade around in their underwear doing whatever the man says.
"There's not enough out there for women to realise this isn't what sex is like and you don't have to act like this."
After the relationship ended, because of problems outside the bedroom, Karen waited for four years before she talked about her experiences properly.
Now, aged 20, and after eight months of counselling - which she says has helped tremendously - her self-confidence and relationships feel more healthy.
She says she does not blame her former boyfriend: "I don't think of him as a rapist.
"I think he was a confused boy who clicked on too many links and found things that he didn't expect to find and thought that was normal and re-enacted it because that's what he thought sex was.
"It wasn't a stranger in an alleyway trying to get his kicks, it was two people in a relationship doing what they thought was normal and acting out the only understanding they had about sex."
This report is based on an interview carried out by BBC social affairs correspondent Michael Buchanan.