Cue-controlled relaxation is a is a way to treat anxiety with relaxation which is triggered by a "cue" in a conditioned response similar to the famous experiment conducted by Pavlov who conditioned dogs to salivate by ringing a bell.
The actual cue used can be anything. Therapists and psychologists who treat patients with anxiety disorders would typically use as a cue a word such as "relax", an imaginary calming scene or a simple physical cue like putting your finger and thumb together. The first step in developing cue-controlled relaxation is to develop and learn a method that enables you to produce a relaxation response such as a state of deep muscle relaxation. See link: http://treatanxiety.co/treat-anxiety-with-relaxation
The next step is to decide on a cue and and begin associating the cue with the relaxation response that you have been practising and learning. For example you might place your thumb and two fingers together whilst practising your deep muscle relaxation exercises. Over a period of time the act of placing your thumb and fingers together with act as a trigger or a cue for the relaxation response.
Psychologists sometimes refer to this type of cue as a relaxation response anchor because the response is anchored to it. Initially the anxiety triggered by conditioned response learning will be much stronger than the relaxation generated by your relaxation response training.
This is caused by two factors: Firstly, we are designed as humans overreact to danger. From an evolutionary point of view, it is much better to mistake something neutral as dangerous than to be harmed by a threat such as a wild animal. Secondly, you will have been unconsciously reinforcing the conditioned response anxiety that you experience for a long time stop even with regular practice your cue-controlled relaxation will by itself probably not remove all of your anxiety.
However with practice it will be able to reduce the anxiety. Cue-controlled relaxation when used along with other skills, if practised regularly, will become an effective tool to treat and reduce anxiety.