My 10 year old son has recently attended a summer camp where he is going to secondary school. He has met new friends which includes a girl. He asked could he take his mobile, to get some numbers of his new friends and take some photos and I said yes. I do talk to him a lot about Internet safety and that sort of thing so I feel comfortable with him using iPads, phones etc and I always check and monitor what he is doing. However when checking his phone I found a message from a girl who is a yeah older than my son which was sexually explicit. My son did reply to this message but not really saying much apart "no". I asked my son who she was and we had a good chat about it and asked him to delete her from his phone, which he did. However a day later I found he was trying to get her telephone number and trying other ways to contact her, like BBM and snapchat. I wasn't happy and he now has had all devices and no computer for a week. What can I do to teach him that this isn't right and this girl is far to young herself to be sending these sort if messages? I know that when he goes to secondary school he will come across all sorts, but I scared for him and I want to do the right thing without getting mad. Many thanks x