Dusty has a thing with Truck rides. You cannot do anything that would slightly indicate a truck ride in front of Dusty. That means you can't touch your keys, shoes, jacket...look at the truck....walk towards the door....say the word truck or ride or goodbye...That included not looking or walking towards the shoe closet or junk drawer where the keys are stored.

Anything to that sort will put Dusty into hysterics. He starts barking like crazy and doing flips.

Roxy, she just likes to 'set up' Dusty. She intentionally drops her bones next to him and walks away. It's her way of testing him. He knows she's boss, and she'll lay and watch. The minute he moves towards it, she pounces on him. She wants him to be the keeper of her bone, but to not actually consume it.