The technique to increase height and control form by creating a cushion or mesh at the base is called:

The technique referred to is backcombing, which involves using a comb to push the hair towards the scalp. This action creates a cushioning effect at the base of the hair, allowing for increased height and better control of the hairstyle's form. By tangling the hair in this manner, backcombing creates a supportive structure, which can hold styles in place for longer periods and adds volume to the hair. The result is a more significant lift and fuller appearance, making it a popular choice for various hairstyles, especially when aiming for dramatic volume or specific shapes.

In contrast, teasing can also refer to similar actions, but backcombing specifically emphasizes the technique of combing hair towards the scalp to create that cushion. Meanwhile, ratting is often used interchangeably with teasing but may carry more connotations of making hair intentionally messy. Volume styling is a broader term that encompasses various methods used to achieve body and fullness in hairstyles but isn't a specific technique like backcombing.