One pupil posted: "if you don't take advantage of a drunk girl, you're not a true Wc [Wellington College] boy," and another said: "f*** women".
School principal Roger Moses has condemned the posts as "deplorable and appalling", and said they do not reflect the values of the school.
Auckland Grammar principal Tim O'Connor said his school adopted the healthy relationship programme into its health education after researching mental health and wellbeing among teens - and pornography addiction was highlighted.
"From the material I've read, too many boys are getting their sex education in the first instance from going online and viewing pornography," O'Connor said, citing statistics claiming 90 per cent of boys have accidentally or intentionally viewed porn, some as young as 12.
"And it's different to pornography of years ago if you're talking the clichéd stuff of centrefolds etc. We're talking now about digital pornography where it's overly aggressive and it depicts women in a really bad light. There's issues with consent and what consent means, because in a porn world there doesn't appear to be such a thing as consent.
"So there's some really good conversation to be had ... If we can ensure they know the difference between an online environment and a real environment and real relationships, as opposed to what they're able to click on at any time of the day or night on a device, then we're alerting them to what harm can be done by viewing pornography and the perceptions they get about relationships online."
The school had worked with Maree Crabbe, an author and campaigner who focuses on sexual violence prevention and the effect of porn on young people.
They held seminars at the school, focused on 4th Form boys and their parents, as well as teachers at the school to raise the subject and open the lines of communication, O'Connor said.
"There's really good reason [to do it], and it's important that we have those conversations with young men, and parents do as well."
O'Connor added: "It's actually about education and if we're going to get it right this will have an impact five, 10, 15 , 20 years down the line as they become men and want to form relationships."
The programme will continue this year, incorporated as part of the junior health programme.
