There are several techniques depending on the "problem" to correct. Some people require reduction in size and shape, others greater volume or correct sagging skin.
Liposuction will improve the shape and volume by combining with liposuction of the lower back and hips.
The Brazilian Lift is about injecting fat grafts (after liposuction) to give volume and firmness, never in large quantities.
To give an adequate volume and long-term result, buttock implants are indicated.