Well,
There are quite a few length exercises, but I personally like these 3: The rotating stretch, Active Isolated stretches (JAI), and the V stretch. They are all great length exercises, and possibly together they are the best combination.
The rotating stretch: Here is a description -
http://www.exercisingthepenis.com/gu...6-stretching-c Active Isolated stretching: Here is a description -
http://www.exercisingthepenis.com/gu...t-guide-10-aos The V-Stretch: Here is a good description with good a good video -
http://free-penis-enlargement-videos...v-stretch.html
If you want to focus on length add 60 JAI stretches, and a few minutes of Rotating stretcges & V-Stretches to your routine.