i think the places u shaded look really good! something i noticed is that it seems the pelvis is angled differently from the model. its difficult to see bc of his undies, but the pose suggests the midline of the pelvis would be leaning more to the left. not sure if what u meant by small is lacking in volume or too narrow, but i suggest focus on the volume. other than that i do love how u defined the muscle groups in the body.
