Focusing refers to a family of introspective techniques taught by CFAR whose aim is to access one's "gut" or "System 1" feelings. Archetypically, sensations within the body are approached with a spirit of gentle curiosity, and possible verbal labels are checked against felt senses. Where successful, this can improve internal understanding and allow split off trauma or conflict between subagents to be processed for improved internal alignment.
Focusing draws in name from the book and technique of the same name by psychologist Eugene Gendlin (Who's also known on LessWrong for the Litany of Gendlin), and since his introduction, some have developed their own variations [1].
Related techniques: Internal Double Crux, Inner Simulator.