First of all, you have to get over your own embarrassment. He will take cues from you on how to react to the information you're giving him. I know it's difficult, believe me--I have a 15 year old son and an 11 year old daughter, so I've been where you are--but that's the first thing you need to do. Get comfortable with the info yourself before you try to present it to him. With my daughter, I actually checked out books from the library, yes, with diagrams, and that helped her to understand a little better. Familiarize yourself first with everything you're going to be talking about, and then encourage him to ask questions, and promise not to make him feel embarrassed. The thing to remember is there really shouldn't be a "big talk," and then it's over. Educating your children about sex should be an ongoing process. He's going to be curious about different things and have questions about things that he might not have even dreamed of when he was 5, and then in a few years when he's dating he'll have even more questions and issues. Keep an open line of communication, and never, ever laugh at him or show embarrassment yourself. The hardest things for me to talk about were masturbation and oral sex, because those were just so...uncomfortable for me to discuss with my kids for some reason, lol, but they had questions so I did my best to be as honest as possible without making it seem like something really gross or something to be ashamed of. He's going to hear about things like this whether you tell him or not; wouldn't it be better to get true information from you than false information from his friends? My final piece of advice for you is not to overload him on information. Let him guide the conversation with his questions and answer the ones he is wondering about right now. In a few months, or few years, he may come to you with more questions, and that's when you answer those. He may just be curious about how babies are made right now, and that's great--give him the scientific information about how everything works, how to prevent unwanted pregnancy, diseases, etc., but he may not need information on other sexual topics right now. You don't want him to think it's something dirty or shameful--just remind him that when he's older and ready, it's a natural process for two consenting adults. Good luck!