What styling technique involves twisting the hair around itself to create defined curls?

The technique that involves twisting the hair around itself to create defined curls is finger coiling. This method requires the stylist to take small sections of hair and wrap them around a finger, encouraging the hair to curl naturally and form defined, spiral-like curls. This technique is particularly effective for achieving well-structured curls, especially in curly or textured hair types, as it provides a more controlled way to create curls compared to methods like scrunching or braiding.

Scrunching is a technique where hair is gathered and squeezed to promote curl formation, but it does not provide the same level of definition as finger coiling. Flat ironing involves using heat to straighten or create waves in the hair, which is contrary to the goal of defining curls. Braiding, while it can create waves or curls if used on damp hair and left for some time, does not specifically involve the twisting motion needed to create defined curls. Therefore, finger coiling is the most appropriate choice for the description provided in the question.