Since the Dawn of Man, males have been diligent (and creative) in their attempts to make their organs bigger. One of the oldest methods practiced by ancient tribes (and still today) is achieved by tying a rope around the head of the penis and stretching it using heavy rocks fastened to the other end of the rope. 

Yes, this method can be successful... but it can also create impotence as a result of too much pressure on the dorsal nerve. Even worse, it often cuts off the circulation to the penis that results in infection and amputation.

While that's not a pleasant image to think about, it at least drives home the point that you could be another 10 inches long within 5 years if you wanted! Until this day no one outside of those tribal communities has possessed the ambition, perseverance, time or desire to make the commitment to become this huge.

Still, I think it's safe to assume that infection, impotence & amputation are not options you wish to consider. And a ten-inch gain in penis length (while o.k. to dream about) is not really a practical goal. Let's aim for a 2" to 4" increase, and achieve it with exercises and supplements that allow you to keep your fertility and your penis. Now that IS an attainable goal!