lol...that would be the six-axis breast motion. If you have the PS3 version (which I'm assuming you do since you have a PSN ID) you'll need to unlock OMG mode (which you can do by losing with 11 different characters). Go into options and select it under breast physics. Be warned that if you pick it the melons tend to have a mind of their own during the fights and go crazy.
Someone correct me if I'm wrong but I think you actually shake the controller in order to move them?