Here, Rusty is playing with his Kong ball, trying to figure out how to get the treat out. Having tried the brute force method (aka eating the ball or chewing it to pieces) he's starting to move it from side to side to get at the treat.
Boo Boo, on the other hand, had a routine that he used to go through: picking up the ball and flinging it in the air, picking it up and shaking it from side to side, rolling it around, and finally banging it against the wall. The steps that he took were impressive and hysterical to watch.
