By Cassandra Morgan

Sexual strangulation is common among young people, with some fearful of being labelled “vanilla” and others ignorant of its lethal danger.

A large university study has exposed the practice as strikingly common among young Australians, with 57 per cent of adults aged 35 and under having engaged in strangulation during sex at least once.

More than half have choked a partner in a cultural phenomenon experts say is most commonly derived from pornography, and then from movies and social circles.

“There’s increasing pressures, particularly on young women, to be adventurous and not vanilla in their sex lives,” study co-author Heather Douglas told AAP.

“They need support to navigate thinking about why they’re consenting, what they’re consenting to, and how they withdraw their consent or determine not to consent.”

Prof Douglas worried many young people were clueless about the dangers of the practice, and emphasised that medical experts say there is no safe method.

“One of the things that we really need to remember about strangulation is that, most of the time, you’re not going to get a visible injury… and yet, it could still be causing harm.”

It could cause brain injury, even when a person remained conscious, and the brain injury could be incremental, getting worse with each choking, Prof Douglas said.

The dangerous practice could also cause miscarriage of pregnancy and death weeks or months after the first strangulation, researchers said.

It can take 10 seconds for someone to be rendered unconscious during sexual strangulation and 150 seconds for them to die, researchers said.

The study found sexual strangulation was gendered, with more women than men on the receiving end, and almost 80 per cent of transgender or gender-diverse young people experiencing it.

About 60 per cent of young people said they first learned about sexual strangulation, often called “choking”, through porn.

It’s Time We Talked project director Maree Crabbe was so concerned, the violence prevention initiative is developing a campaign about it.

She spoke to young people who said sexual strangulation was normalised, could feel scary and unsafe, and often happened without communication or consent.

“Particularly young women talk about feeling like they are prudish or vanilla … if they’re not prepared to engage in sexual strangulation,” Ms Crabbe told AAP.

“Pornography has become a default sexuality educator for many young people in a way that it wasn’t 25 or 30 years ago – or even 15 years ago.

“Half of boys have seen pornography by the age of 13, and half of girls have seen it by the age of 15.”

Matilda, who was involved in the Breathless campaign under a pseudonym to protect her identity, said choking was “very mainstream”.

When people were on the receiving end they just had to expect their partner would stop at the right time, the 18-year-old said.

“I’ve never felt scared at the beginning of being choked and I don’t know why – I probably should,” Matilda said.

“But as it goes on you know the longer you’re not breathing for the more sort of panicked you get and the less, you know, mobility you have.”

Experts told Ms Crabbe there was an “explosion” in harmful sexual behaviour by children and young people towards their peers, and pornography was a big reason behind it, she said.

The experts said children under 10 were engaging in more violent, more abusive, more “adult” forms of sexual harm against other children, Ms Crabbe said.

“That’s the pointy end that tells us very clearly that something’s not OK,” Ms Crabbe said.

“Pornography – (which) is a global, multibillion-dollar industry – is setting the agenda around what sexuality looks like it and how it’s experienced with enormously detrimental effects.”

More awareness is needed about the prevalence and dangers of sexual strangulation, and encouragement for young people to think critically about why the practice was normalised, Ms Crabbe said.

Social media companies’ lack of accountability and regulation also meant misinformation about sexual strangulation was spreading without recourse, she said.

Prof Douglas added parents needed support to talk to their children about pornography and strangulation.

Canberra Health Services forensic medical specialist Jane Van Diemen, an expert quoted in the Breathless campaign, emphasised there was no safe way to be strangled.

“I’ve been working in this field for 15 years,” Dr Van Diemen said in the campaign.

“Even knowing as much as I do about strangulation, I cannot predict the point in which strangulation is going to end up in irreversible damage and death.”

The sexual strangulation study findings, by researchers from the University of Melbourne Law School and University of Queensland, were published in the Archives of Sexual Behavior journal on Tuesday.

On average, people involved in the study of more than 4700 young people reported being strangled six times by three partners.

People were usually first strangled by a partner between the ages of 19 and 21.

Federal Communications Minister Michelle Rowland welcomed the latest steps towards mandatory industry codes to protect children from online pornography, as flagged by the eSafety commissioner.

“The new codes will create obligations on industry to restrict access to age inappropriate content on their services,” the minister said in a statement on Tuesday.

The codes, in line with the Online Safety Act, will apply to app stores, internet service providers, pornography websites and sites where children unintentionally come across pornography, like social media and gaming sites.

Ms Rowland said the government’s recently funded age assurance trial will complement the codes.