You may or may not have seen this new video initiative from the NSPCC, but if you haven't I would urge you to watch and share it with your children. I sat and had a chat with L (11) & H (9) about the video, before watching it with them, and then we talked about it after.
I think that this video is a great tool for striking up a conversation about what can feel like an awkward subject with kids. I have always been open and honest about these things with my children, but I understand completely that others do not find it easy to do so. Have a watch, and read the NSPCC's guides to social media and online safety, and help keep your kids safe on the internet - teach them to be #ShareAware.