CAB-Chaser
You must first understand what the PX is. Military bases have a general store, which is officially known as the Post Exchange. Everything from military equipment to candy snacks is available. A PX ranger is a soldier who has over-equipped themselves with PX equipment. The inference is that they’ve probably overburdened themselves with goods they don’t actually need.
Beat Your Boots
Regardless of how upset they’ve made you, hitting your boots is a waste of time. Because shoes are inanimate and don’t care what you do to them. In the military, though, thumping your boots means leaning down to touch your feet and then snapping erect. It’s a difficult workout, but it’s an excellent punishment for little infractions.