Cat Laying Down On Back. They made their own “beds” in nature. A bite or claw can't really hold on to the body beneath and so can only deliver a flesh wound and the cat can still maneuver to fight back.
Often cats have issues with being brushed. To make their sleeping quarters more comfortable, cats would pat down tall grass and move prickly underbrush and stickers before. A cat's skin is elastic all over (look at a hairless cat for visual) for the same reason a sharpei's is: