Coveting

So lately, I've been feeling a little insecure about my scooter balls. They're those little green tennis balls that I get to chase in the back yard. Problem is, they get all dirty and slimy when we play, so Mami always puts them up when we go back inside. I caught onto that really quick, so I started not giving them back to her, and then she had to fish them out of my mouth, which got me really mad.
But lately, I've gotten paranoid about her taking my ball away, so much so that half way through a good game of catch I decide not to let her pick it up and throw it any more. I do it to Papi too. They get annoyed, because then I just carry the ball around and look grumpy, and the game's no fun for them. It's not fun for me either, but I get worried that the next time, they'll just take the ball back into the house.
Mami's finally started letting me carry it inside, which has helped, but then she always tricks me at the end by giving me peanut butter treats, and I have to drop the ball to eat them, and then it disappears. I guess I"m going to have to work through this on my own cause otherwise catch is going to stop being fun.