For me, everytime that i plug and unplug the USB cord, i can feel the phone move. Easiest way is to put the phone into the back hard plastic cover and move your phone. You should have some movement. I have had 2 Defenders (early & late release) and RealTree do that. I use anything really for cushioning...electrical tape folded in two, paper, etc.. All work well. The main thing is to avoid movement within the case because if sand particles etc. get in there, the rubbing will cause damage to case and/or screen. Remember, although your screen is Gorilla Glass 2, it can still scratch easily with sand particles rubbing against it. (I wish that future screens be made of sapphire!)