When you PMO consistently the body brain/body grows accustom to it. So when you suddenly stop, the brain sees it as deprivation, and so reacts by craving the activity aka creating an urge. Screen time usually numbs the urge while sugar arouses it. This is just my experience.
Excessive TV changes the neural pathways in the brain leading to desensitization. I would add that this is likely dependent on what you are actually viewing.