I don’t know what to do:/

So last year, my brother and I have the best sex of my life felt so good. Every time I think about it, I instantly get turned on. It only happened once however we’ve been talking recently and we both agree that we want to do it again. I’ve masturbated with him on the phone every time I masturbate I think about him. We just exchanged a couple of pictures of each other and every time I look at his picture I want it so bad. The problem is I would die if my family found out because although I don’t have a problem with it, I know that family would not understand which brings me to the problem because we were on the phone a couple of days ago and I got the feeling that he’s gonna rat me out. I figure if I just keep it as the one time I can always say it was a mistake, but I feel like I need it. What do I do?