I didn't want to leave you hanging, so I'm hoping to be inspired here.I'm no expert, but I agree, instead of just doing something "behind the scenes", I would try to approach him directly. Try of course to give him a perspective of understanding. The fact is God made some woman very beautiful. It's not an excuse for porn by any stretch, but it can be a stepping point to ease into the conversation. What you need to explain to him is that God never intended us to look at woman in that context, and not only is doing that offensive to God, but it encourages and support the very industry that leads you woman who are mothers, daughters, sisters to do something horrible with their bodies for money.I might also explain the notion of a virtuous woman, ask him who does he see his wife being in the future. I don't know his age, nor how you two relate, and he might say, "well dad, I want one of them!" I think he needs to really look at who he wants to be with and what kind of person she will be. And how porn may degrade that image in the future, even to a point that he may not understand what loving a woman really is.The most important that you have to talk. Be firm with your son and get him to understand that this is unacceptable behavior, but look him in the eyes and love him the whole way through.