For those who haven't experienced Boomer in the pool, the rule is that before you jump into or move anywhere in the pool, you have to know where Boomer is, because he will not watch out for you, and he will not hesitate to jump on top of you or plow you over if you happen to be in the way of the ball or the steps. But, he does share. He will make sure that everyone around the pool gets a chance to throw his ball (or toy, or frisbee, whatever the current choice is). He will also bring it "closer," albeit grudgingly, especially if he thinks it's already close enough. (Sometimes, I wait for him to run to the other end of the pool, then pretend I can't reach it and say "Closer!" to make him run all the way back around just to nudge it an inch closer with his nose. Messing with the dog is almost as fun as messing with the kid, sometimes.)
Boomer. Ball. Pool. Enough said.