It's hard, Trent. My daughters take a strongly anti porn stance because of how they have encountered it through other children and haven't engaged with it. But peer pressure is terrible and as much as I can switch on parental controls, other parents don't and trust me, most teenagers can circumvent them in a blink of an eye anyway. Also parental controls generally come from the States and not only censor porn but swearing (which as a parent I'm not fussed about) and, very often, LGBTI issues, which I want them to be able to engage with.
I have no clue if I'm getting this right but I've found the best thing is actually to be a friend in a way, and talk about stuff that I gather most parents don't talk to their kids about, including labia size and goodness knows what else. My girls also happen to follow a lot of young feminist activists on social media and maybe some of that will rub off on their little bro. The only option is to talk about it, talk about it and talk about it some more.