Wish more guys would give their insight here. With a few more posts we could probably sum up what is working for most people, breaking it down between manual and device related exercises.
I dont know if I want to say the exercise that has helped me the most because I have only been going for 4 months. I have gained about .5 inches in girth due to jelqs, but L.A.S. and Bundled stretches have also helped me a ton!