A "lovely fetch game"

I was reading on the sofa while Henry and Walter played in the kitchen.  I wasn't paying too much attention as there was no crying, no whooping, nothing to get worked up about - then certain words and phrases caught my ear.  Things like Henry saying, "sit," listening to Walter pant, and then hearing him occasionally leave and venture back to his brother.  I started peeping at them from my comfortable spot, and stifled laughing outright as they continued to play "fetch" - Henry the person, and Walt the dog.  They played their parts quite well:  Walt fetched the toy dinosaur and delivered it to Henry, happily, in his mouth.  He panted like any dog who was running around might.  Henry, prior to throwing the toy, firmly and kindly requested that Walter sit first, and upon hearing a plunk on the floor, I figured his brother followed the direction appropriately.  Hen would throw the toy and Walt would dutifully trundle after it.  This went on for longer than I think Walt should've played that role, personally, but then ended abruptly as Walter walked away saying, "No mu-ee", which translated into his language means: "no more". 
Henry said, "That was a lovely fetch game."