Mobilization is defined as a manual therapeutic technique that fosters movement in stagnant tissues and joints.
Mobility exercises tend to have a calming feeling and will help you release stress. They improve your range of motion and will prevent the stiffness that comes with muscle build-up and strength training. They can be a low-intensity exercise that will give your body a break and help it heal from high-intensity training.
Basically, mobility exercises are warm-up exercises that help prepare your joints for a workout. Remember that when performing mobility drills, there's no need to hold your position; the emphasis is on movement.
Give this simple movements a try for your hips and upper body.