It's easy math to do. Lets say you get 20% expansion with any given jeqing routine. If you start jelqing and get 20% expansion but you are jelqing at 80% you really are accomplishing little. Once the 20% is worked in your penis would be at 100% of it's biggest size. This does little for growth. If the same penis is trained at 90% erect and get the same 20% expansion, he now is seeing a 110% expansion! This is where he wants to be. Sometimes going 100% erect is difficult to do but with practice and strength of hands you will be able to jelq 100% erect and score 15-30% expansion, now you can be sitting at 130% temporary increase. If you are able to hold that for some time you would really have something.