Gluteal implants offer a good way not only to correct hypoplasias, but also to remodel and give rounded shape to buttocks, achieving beauty and sensuality. However, until recently, only a few surgeons have used this procedure. An intramuscular introduction of the implants may be a good means of reaching this goal, but because the undermining is performed without direct view, difficulties may occur in obtaining a symmetric and safe plane, and this can lead to unpleasant results. This report presents an intramuscular method based on geometry, in which three points (X, Y, and Z) and a line (G) in the pelvis define the plane in which the dissection must be performed, allowing more precise and safe undermining. From 1986 to 2003, 746 patients underwent surgery using this technique, achieving good results. This technique has proved to be a safe and reproducible way of performing augmentation gluteoplasty.