Because slobbery ball adds to the fun

Love the outfits on these two! But this isn't just a game of catch-- I think there's something, ah-- edgier about this. They're standing so close to each other, and Norman looks like he really threw that ball hard with his arm outstretched like that. I think what's going on is they're hucking the ball as hard as they can at each other, like some kind of pain-threshold challenge. Seamus might have just gotten a quick or lucky move in and caught the ball with his teeth before it smacked him in the face.

Heh. They may be 4-5-year-olds, but they are male canids. Never thought of that, but it wouldn't surprise me.
The things "friends" can do to each other.~