The only thing I know of for sure that works is based off surgery.. A good amount of the penis is inside of the body and one surgery involves streching the tendons that hold it in place.. There are devices that you can buy that are worn mostly during the night while sleeping. But these work on streching the tendons.. It is a process and it will take time to truely notice anything and by time I mean years.. 3-4 years will prob get you around 2".. I know this process works because when I was 19 I felt I wasn't as big as I wanted to so I gave it a shot.. I'm now 22 and sit close to 9", i've gotten many a surprised face, so it def works it just takes time.. I actually prefer it over the idea of surgery.. Only side effect with it is that hair from the base of the penis will move up slightly onto the shaft, maybe a half inch, from the streaching, but its hardly a big deal. Best of luck, and I know it takes a while but totally worth it..