you know i ask my self the same thing , i used to do [words=http://www.mattersofsize.com/forum/penis-enlargement-forum/12539-slow-squash-jelq-nothing-give-me-better-expansion.html]ssj[/words]'s at a very high intensity so much that i would have bruising and burst capilaries after every session. also i found that after a certain amount of expansion my dick wouldnt epande any more no matter how much intensity i used my dick would just start to go limp wich made it impossible to continuasly get hard as i said above i would get sever burst cap and bruising . ps. this also shortened my session dramatically not only becaus my cock would look horrible but becaus i would not be able to get fully hard after only a very short time of doing high intensity [words=http://www.mattersofsize.com/forum/penis-enlargement-forum/12539-slow-squash-jelq-nothing-give-me-better-expansion.html]ssj[/words]'s id say 4-5 times so i would just barly get expansion!
ive just recently started trying to hold the grip for longer and only use moderat intensity and already my session are very very long , i can get erect over and over again without exhaustion and i am expanding more so its pretty sweet. then again everyones different!