I totally agree with Rhadadames with sharing some of the normal, intimacies such as letting him watch you pee, and showering with him, and, basically, just being comfortable with your body in front of him, whether you are both clothed or naked.
I have a 16 year old son, and I have realized that children seem to get the most valuable lessons from what you demonstrate to them as much, if not more than what you tell them. If you are demonstrating a healthy comfort with your own body in front of your son, and with your son’s body as well, then he will pick up on that positive feedback and get more from that than anything.
There is nothing that my son and I are embarrassed about sharing with each other in conversation now, and I truly believe it is because I had made it a point to be comfortable giving my son all the information he asked for as he was growing up, and also demonstrating unconditional love and acceptance for him.
Though he is a very handsome boy, and even better hung than I am, lol, that is the minor stuff, actually. He has learned through our relationship, that regardless of what he looks like, or ever looks like in the future, and regardless of what mistakes he makes, there is nothing he can do that he could not tell me, or that would ever change my love for him. I have also taught him that if there is something about yourself that you can change, then change it, but never at the risk of your health. If you cannot safely change it, then it is always possible to learn to fully love and accept yourself the way you are.
I have taught him to not determine his, or anyone else’s worth by appearance, rather, to look at the heart and go from there. When he was a toddler and at the constant questioning age, he often bathed with me, and asked all kinds of questions about his own body and mine. I had no problem allowing him to explore his own body and to examine mine. As unorthodox as that may seem, I never did anything sexual with him, just for the record. He was just curious and asking questions about similarities and differences, and if he will look like that someday, all the normal stuff kids ask. I always answered his questions as he asked them, and it just seemed to flow as naturally as teaching him how to shave after he went through puberty.
I did opt to tell him about jelqing and strengthening your pelvic muscles. I told him early on, because I know that strengthening those muscles at an early age means better blood flow, better control over your urine and bowel functions, and healthier sex with good control and stronger orgasms. I just added that gaining increase in size is a nice bonus, but that some people opt to use jelq for size alone. I don’t think that you should put it to a kid that jelqing and doing the exercises just for size should be stressed to them in a way that makes them feel inadequate about their bodies. I think everyone should jelq and exercise because it’s just a healthy thing to do, like working out the rest of your body is good for you. With both types of exercise, whether it’s your biceps, or your sex organs, possible increase in size is just a bonus.
This also coincides with wadatah510’s reply. The main thing, I believe, is to give kids the freedom to know that they can come to you with any question about anything and know that you will be there to answer, or help them find an answer, or just be there when there is no known answer. It’s all about an honest, open, transparent, loving relationship. Be willing to let your kids learn from your own experiences and even your mistakes, and it will save them from having to repeat a lot of the bad stuff.