How do I add Animation smoothing when ending a animation?

When a animation has ended, how do I make it go back to idle smoothly? Basically as if I was to lerp it back to idle position. Mocap dancing does this if you want to know what i mean.

Just leave extra time at the end of the animation, like if you want the Smoothing part of the animation to last 1 second then leave 1 second of empty space at the end of your animation when you're in animation editor.