Imagine trying not to blink, resisting the urge to sneeze or refusing to scratch an intense itch. For a short time, you can probably succeed, but the effort becomes increasingly untenable until the urge eventually wins.
People with Tourette syndrome describe tic suppression in a similar manner. Tourette syndrome causes tics, or repeated movements and sounds, that a person cannot always control. These tics often come and go, change over time and may occur along with attention problems, anxiety or obsessive-compulsive behaviors.