If you hold down the upper face buttons, Y or B, a menu will pop up based on your settings. These will generally be expressions of the basic options in the Expressions options. IF your avatar comes with unique options or animations, then these will show up instead. Some creators even organize this menu with submenus relating to the option you are adjusting. See The Void (Avatar Hub) for an extraordinary example of this for multiple avatars. Psst. It's number one on this list. Most avatars also come with the option for certain gestures or button presses to cause certain changes on the avatar. This might be simple as the expression changing to something more drastic, like performing ritualistic magic. See Toga and Ikka Avatar for several selections that uniquely play with this option type.