What's supposed to happen is that you hold the attack button (left mouse, by deafult) for however long, then release, and the shield goes away, and you can move freely again. If you press alternate fire (right click by default), then Gohan launces the shield in a small ball which causes more damage depending on how many attacks the shield absorbed. Otherwise, I haven't really seen any problems with the shield attack yet....it used to supposedly crash servers, but I haven't really run into that problem myself.