Systematic desensitization involves a series of steps, which occur over several therapy sessions: The therapist and client make up an anxiety hierarchy. The hierarchy lists stimuli that the client is likely to find frightening. The client ranks the stimuli from least frightening to most frightening. 
The therapist teaches the client how to progressively and completely relax his body. Next, the therapist asks the client to first relax and then imagine encountering the stimuli listed in the anxiety hierarchy, beginning with the least-frightening stimulus. If the client feels anxious while imagining a stimulus, he is asked to stop imagining the stimulus and focus on relaxing. After some time, the client becomes able to imagine all the stimuli on the hierarchy without anxiety. Finally, the client practices encountering the real stimuli.