Inertial Bounce is like making your moves "rubbery." Layers will overextend, then settle into place on position and rotation keyframes. I honestly don't remember where I found this expression, but you can find it in a bunch of different places now.
amp = .05;
Yet another awesome thing. How to link a 2D point to a 3D point (like a light or a 3D null) and it's hella simple. Find the tutorial I got this from Video Copilot. You know who they are... and if you don't, PLEASE check out their large library of tutorials.
1- Alt + Click the 2D position value
2- Pickwhip the 3D layer then add ".toComp([0,0,0]);"
The loop expression takes keyed animation and does something immediately after.
It'll either PING PONG, (go back and forth with the animation)
CYCLE, (which loops the animation from the beginning over and over again)
or CONTINUE (which keeps the value of the animation going in that direction)
loopOut("one of the 3 options"),