Other than placing buttock implants within the gluteus maximus muscle (aka “intramuscular”) NOT “subfascial”, the most important factors in creating the perfect derriere and/or hourglass figure with implants is indeed selecting the right size AND shape. I have found the best way to assure this is to simply measure the actual dimensions of the patient’s buttock cheeks and quantity and quality/density of the underlying gluteus muscles. With these anatomical measurements, I can select an implant that not only significantly augments the buttock but also supplies the correct 3-dimensional enhancement to look as real as possible...even in the most petite patients. Note, height and weight are considered but not nearly as relevant as the above measurements.Unlike breast implants, silicone gel buttock implants are not FDA approved and thus not legal for buttock implantation in the USA. I actually see about one patient a week that had gel implants done in another country and, although they looked a felt great at first, they are now seeking revision because the implants are either visible on top of the muscle and/or grossly deformed by flipping over, rotating, scar contracture and/or the implant has ruptured several years after placement leaving behind hardened scar tissue and migration of silicone liquid. The soft semi-solid silicone rubber implants used in the USA are much less likely to have these problems if placed correctly within the gluteus muscle AND are considered permanent implants because they cannot rupture and leak silicone gel. In 2015 I created and recently patented a new "Stanton Anatomic" shaped implant that avoids the unnatural effects of round implants, whether silicone gel or rubber . The benefit of this is the fact that ~95% of patients have much more of an oval shaped buttock cheek not round, thus a true oval implant (i.e. Stanton Anatomic implant) creates a much more natural and harmonious buttock contour. This is especially true when the patients bends over, does squats, or pokes their butt out while striking a pose or dancing. Many avid weightlifters, fitness competitors, and athletes from various sports have had these implants without problem of movement, visibility, or drooping. Glad to be of help.