If I knew what the problem was, maybe I'd have a solution
So little Johnny (or Jane) sees porn. If they are young, they giggle and get back to something interesting like Minecraft. If older, they get aroused, have a wank, then get back to something interesting like Facebook. Not sure I see at what stage there is any damage caused, unless there is concern that it might interfere with the pro-ISIS indoctrination of our disaffected youth.