Peer pressure to appear 'cool' forces many teenagers in South Africa, like 14-year old Dlamini, to take part in actions like starring in a sex video and posting it on the Internet.
"Being a virgin is not cool at all," said Dlamini (not her real name), describing the peer pressure she faces.
"Having the latest cellphone or wearing designer clothes doesn't make you cool anymore. You need that extra little something that will make people take notice," she told AFP.
"If you take pictures of yourself posing sexy or better yet have a sex video and post them on Facebook or circulate them... maybe you will be cool."
With 13.7 percent of pregnant teenage girls testing positive for HIV, according to official figures, risky behaviour in this group illustrates the challenges still facing AIDS education campaigns.
The core of the government's prevention programme has been "ABC" -- abstain, be faithful or condomise -- in a country struggling to deal with 5.63 million infections.
Risky sexual behaviour among high school pupils dropped slightly in 2008, with 38 percent of pupils having had sex down from 41 percent in 2002, according to a survey released this year by the Medical Research Council.
The number of pupils reporting two or more sexual partners dropped from 45 percent to 41 percent, revealed the survey of more than 10,000 teenagers aged from 13 to 19 which drew comparisons with the 2002 baseline study.
But only 31 percent of sexually active students said they regularly used condoms, and nearly one in five had been pregnant or made someone pregnant.
The low condom use is despite 65 percent having received HIV and AIDS education.
"Sexual coercion is very common, and girls are often unable to 'choose' safe sex or to access contraception," said Rebecca Hodes, deputy director of the AIDS and Society Research Unit at the University of Cape Town.
Dlamini said condoms can be difficult for teenagers to obtain even if they want them.
"It's not easy getting a condom because most people are shy of going to the garage and buying condoms and going to the clinic because nurses will humiliate you. So people rely on older friends," she said.
Botha Swarts, a spokeswoman for state-funded prevention organisation Lovelife, said peer pressure has "a huge role to play" in young people's decisions about sex.
"Seventy percent of calls received at our call centre are from young people who are peer pressured into doing things they are not ready to, for example sex to prove love, smoking, experimenting with harmful substances," she said.
A scandal at a Johannesburg high school caused outrage over a video clip showing two boys and a girl having sex while watched by a group on school premises after it was circulated on mobile phones and online.
AIDS education campaigns also face an uphill battle to counter the messages modern teens get about sex.
"Safe sex campaigns are trying to respond to this bombardment of messages from other sources, to encourage young people to protect their sexual health, but they must also contend with the realities of adolescent life in South Africa," she told AFP.
"What is often sexy to adolescents is the idea of risk itself. The power and mystique of raunchy, casual sexual encounters is promoted perpetually by the mass media. This is very difficult for safe sex campaigns to counter."