Thank you for that additional information. Without knowing exactly how many inches your penis is though, its impossible to say whether or not yours is in the normal range. Many men feel their penis is too small or too narrow, but actual studies show that the average penis length is between 5 and 7 inches erect,and 3 or 4 inches flaccid. And contrary to what messages media may convey, most women truly do not care...in fact, a super size penis can cause sex to be painful. You are probably not going to like my answer to you, but there really are no safe and approved methods of penis enlargement.
You may have read about penis enlargement methods...all are risky and all have been condemned by major physicians organizations. Below are some examples of them, and are NOT recommended. The Mayo Clinic has written about some techniques you may have heard about. The next few paragraphs paraphrases what they have to say about those methods, and I repeat they are NOT recommended.
There are exercises where one squeezes the penis, called "jelquing". In this practice,a "hand-over-hand motion to push blood from the base to the head of a semi erect penis, are supposed to be performed on a regular basis." Though the Mayo Clinic website says this method may be safer than some of the others, it can still result in pain , deformity of the penis, and scar tissue formation. And no studies show this method to be effective at increasing penis size.
Some people have attached weights to their penis, hoping to stretch it. Again, its NOT recommended and can lead to permanent damage. There are pills and lotions advertised, but none has been proven effective or safe, even those which claim to have testosterone and hormones in them
For those who have a pathophysiological problem with erection, vacuum pumps can be effective as they draw blood into the penis. But for those with normal penises, use of a vacuum pump can cause damage to the tissues of the penis, resulting, long term, in erections that are not so firm.
Surgical techniques can include severing the ligament that helps to attach the penis...while this may make it seem longer because it hangs lower, it can cause the penis to have difficulties while erect. Fat has also been injected to make the penis seem wider, however, it can settle wrongly resulting in a deformed organ. I repeat that none of these are safe, and none is proven effective, and major physician groups have come out against these methods.
There are things you can do, however, to safely make your penis appear bigger. If you are carrying a lot of fat on your abdomen, as you write that you are overweight, that can make the penis seem small. Getting into shape can therefore make the penis appear larger as it is not dwarfed by a large belly.
Here is a website regarding penis enlargement, and the reference source I used for the information above. http://www.mayoclinic.com/health/penis/MC00026
Having said that, here is a website from a urologist who specializes in penile surgeries. I do NOT recommend this, but I include it for completeness, and that fact that informed decisions require that as much information as possible be made available so an informed choice can be made. http://www.drwhitehead.com/
If your penis does fall below the normal for its size, you may have a testosterone imbalance. A referral to an endocrinologist for testing testosterone levels and possible treatment options would then be worthwhile.
I hope I was able to help. Please only rate my service to you when you are satisfied with my answer; thats how I get paid here. If you have any other questions on this topic or feel dissatisfied I am more than willing to work with you further. As I wrote before I think you are quite wonderful to be asking this question.