This is one of the 6 key processes in ACT (Acceptance and Commitment Therapy), which is based on RFT (Relational Frame Theory).
Defusion involves the creation of nonliteral, nonevaluative contexts that diminish the unnecessary regulatory functions of cognitive events, and increase contact with the ongoing process of relating as opposed merely to its products. Said in another way, the focus is on mindfully noticing thinking as it occurs. Some examples of defusion techniques include thanking one’s mind for a thought, watching thoughts go by as if they were written on leaves floating down a stream, repeating words out loud until only the sound remains, or giving thoughts a shape, size, and texture. Clients can practice labeling the process of thinking (e.g., “I am having the thought that I will never be successful”), and practice behaving in ways that directly contradict a thought (e.g., saying “I cannot walk” as one walks across the room). The goal is greater behavioral flexibility, not an immediate change in their frequency or form.
Defusion involves the creation of nonliteral, nonevaluative contexts that diminish the unnecessary regulatory functions of cognitive events, and increase contact with the ongoing process of relating as opposed merely to its products. Said in another way, the focus is on mindfully noticing thinking as it occurs. Some examples of defusion techniques include thanking one’s mind for a thought, watching thoughts go by as if they were written on leaves floating down a stream, repeating words out loud until only the sound remains, or giving thoughts a shape, size, and texture. Clients can practice labeling the process of thinking (e.g., “I am having the thought that I will never be successful”), and practice behaving in ways that directly contradict a thought (e.g., saying “I cannot walk” as one walks across the room). The goal is greater behavioral flexibility, not an immediate change in their frequency or form.
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635495/