Enhancement of the shape of the buttocks is a popular procedure that I prefer to do by using fat augmentation. So, yes, absolutely you can take fat from the stomach (or basically any other area of liposuction) and use it to augment the size and enhance the shape of the buttocks.
This "brazillian butt lift" procedure utilizes a combination of liposuction to sculpt and enhance the curvature of the low-back as well as the frame around the buttocks and fat transfer to the buttocks.
The treatment is individualized to your anatomy and goals, and typically requires a significant volume of fat to be harvested from liposuction and transferred to the muscle and subcutaneous fat planes of the buttocks (up to 400-600 cc transferred to each buttock).
Buttock enhancement as I described above is preferred over using butt implants where possible in my practice, and is a highly rewarding procedure. Dr. Nguyen's estimate of $6,000 is a good starting point, although there are variables that can't be sorted out without a personal consultation (with the amount and number of areas of liposuction planned affecting the cost).
Hope this helps.
