Final answer:
The spiral technique in hairdressing is most often used on long hair to create spiral-shaped curls or waves for a glamorous look.
Step-by-step explanation:
The spiral technique in hairdressing is most often used on long hair. It involves creating spiral-shaped curls or waves throughout the hair using a curling iron or other styling tools. This technique adds volume and movement to the hair, and is commonly used for special occasions or when a client wants a more glamorous look.