The NSPCC is trying to spread the safety message to parents and children
Police are visiting every school in Wales to warn pupils of the dangers of “sexting”.
As well as cutting down on cyberbullying, there are fears young people do not know they could be breaking the law by sending sexual images.
It comes as Safer Internet Day is highlighting online safety.
A new survey found 30% of 11-16-year-olds experienced unkind online behaviour in the last year.
And 75% of youngsters blocked someone.
The ResearchBods study also looked at how much time young people were spending online, with 55% saying they interacted with their closest friends several times an hour.
Police have started warning teenagers of the legal aspects of what they text – and aim to have visited all schools by the end of the year with the “Think Before You Click” message.
One of those going into schools is PC Richard Norris, of South Wales Police.
He said sharing explicit material can be an offence in itself, even if you are not the originator.
“One click can have a massive impact,” he said.
“The knock on effect it has with jobs, career, the embarrassment or even to the extent of someone hurting themselves over it. We want to reduce and stop this.”
The NSPCC has a Share Aware campaign aimed at parents of eight to 12 year olds.
The children’s charity says its own survey in 2013 found 40% of teenagers had created a sexual image or video.
Meanwhile, pupils, teachers and parents are meeting politicians at the Senedd to push for online safety to be taught in schools.
The Welsh government has also organised e-safety awareness raising activities in schools across Wales
First Minister Carwyn Jones said: “While we actively encourage young people to embrace the internet’s huge potential, it’s vitally important they are equipped with the skills and knowledge needed to do it safely and responsibly.”
“The research we did recently, which is in my book, found that kids aged 9-12 and then 13-17 don’t quite understand where they cross the line from jokes and flirty fun when sexting or distributing intimate images to where they are actually breaking the law.
“It’s everybody’s responsibility. If it involves classmates there’s an obligation to the school but it’s important that parents are involved.
“Research has always focused on children’s behaviour online but we need to look at the systemic forms of misogyny, homophobia and discrimination – these are the forms that sexting and cyberbullying are rooted in and adults are the worst models of this.
“Until we address what adults are doing we really can’t blame the kids for copying us.”