Even while your children are quite young, you could say to them: “If you ever come across an immoral website and you feel tempted to look at it, please come and talk to me.
اِسْأَلْ نَفْسَكَ :‏ ‹ مَاذَا يُمْكِنُ أَنْ يُغْرِيَ وَلَدِي بِٱلنَّظَرِ إِلَى مَوَادَّ إِبَاحِيَّةٍ ؟‏