We need to be explicit with our sons to stop bad things happening - like doing things to girls without their consent, Michele A'Court writes.

OPINION: When my daughter was a teenager, each time she and her friends left our house, frocked up for a party, I'd call down the stairs, "Have fun! Be safe! Count your drinks! And remember, you can always phone me!"

I had promised her, made it clear many times, that no matter the time, no matter where she was or what state she was in, I would come if she called. Once, she did call. I drove across town in my pyjamas. We were pleased to see each other. We saved interrogation and explanation for the next day.

I was grateful for mobile phones. I couldn't always reach her (they never answer) but I knew she could always reach me.

When I was a teenager and bad things happened, we would sometimes wish we had some kind of evidence – a photo, a message trail – to prove something untoward had occurred. So it wouldn't only be your word against his. The risk of it turning into he-said-she-said usually meant no-one said anything at all. Imagine, we would sometimes think, if there could have been a picture?

Today, there are pictures. Except instead of acting as evidence of a crime, the picture is the crime. Something bad happens, it is photographed, and posted on social media. Where it remains forever.

Once again, this weekend, we're hearing of a group of young men who are holding a competition where the girl is the prey. The winning boy is the one who gets the most young girls drunk, dangles his genitalia over their faces, takes pictures, and posts them on Facebook.

Police have used their discretion to not prosecute these boys for sexual misconduct or assault, and have let them off with a warning. It is, police have said before, hard to win a case when the victim can't effectively give evidence because she was barely conscious.

Another thing that is hard to do is to find anyone this week who agrees with the police. School principals, counsellors who treat adolescents with sexually harmful behaviours, and rape prevention educators are asking for criminal charges to be laid in this case, and they recommend mandatory treatment.

Teenage boys, they say, don't have the developmental maturity or empathy to understand the consequences of their actions. They need the lesson, or they won't stop.

What drives them? Our children are getting their sexual cues from pornography. The porn they have access to is explicit. Possibly more explicit than their parents have ever seen.

So we need to be explicit with them. When our sons are leaving the house for a party, we should call down the stairs: "Have fun! Be safe! Don't dangle your genitalia over anyone's face! In fact, don't do anything at all without her consent! And remember, to give consent, she must be conscious!"

And we should tell them that if it feels like something bad is about to happen, the only appropriate thing to do with their phone is use it to call us to come pick them up.

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