OK before I start, I ought to say I don't have a problem with DS wanking, watching porn, or in fact having sex (he has a gf).
What I do have a problem with is him watching porn on the family computer which his siblings use, without deleting the browsing history or attempting to cover his tracks in any way. He has a 10yo sister and an 11yo brother and I really wouldn't want either of them seeing most of the stuff he'd been looking at. And seeing as I discovered it by accident (clicked on "Favourites" to get to my emails, and a whole list of the History came up including his porn) it's feasible that at some point one of them will innocently do the same.
I am also a bit about it because he has a laptop and I can't quite work out why he couldn't have watched it on there in the privacy of his own room. The wireless connection is a bit temperamental but usually it isn't long before it comes back on, and DS knows that. But it seems instead of waiting for it to come back on, he must have sneaked downstairs (this was at about 2 in the morning btw), switched the family PC back on and visited several porn sites on there. There may be a "good" reason for this, but it does make me think that he might have developed some kind of habit/addiction as he seemingly couldn't even wait twenty minutes or so till the internet on his laptop started working again.
I guess the reason I'm asking is that I don't really know what to say to him. I think I need to say something to make sure he knows to delete the history if he looks at anything dodgy on the downstairs computer, but I don't know whether to say anything else as well? Also, should I talk to him about it myself or would it be better coming from DH? I don't want to embarass him or make him feel it's something shameful but at the same time I don't want his younger brother/sisters to see anything they shouldn't.
BM x