THE BALL NOW HAS A TAIL AND LOOKS LIKE A SPERM! ( ͡° ͜ʖ ͡°)
I started by researching how other animators have planned out the movement of a tail: (it was actually quite awesome how many of my Youtube friends and peers appeared when I researched this)
Generally, a tail will reflect how fast a character is moving. If it flops up and down drastically the character may not be moving very fast, like a squirrel, for example. But if it follows the main line of action of the character or creature (owner) with very little or no flopping then the character is moving very fast. I remembered this for the animation and tried my best to create the believable movement of the tail as it followed the line of action of the ball as well as responding to the drastic change of course like when the ball hits the wall or platform.