Help! Butt is too big for Stella McCartney Indio White Trim Zips at Ankles

These are Rare..... Stella McCartney in Indio blue with white trim detailing the details on these most excellent pants, which I wish more than anything would suddenly fit. Dark blue, almost black. Zips at ankles Slim Fit Front and Back Pockets. Waist Flat: 14.5 inches Rise: 9 inches Inseam: 29 inches Hips Flat: 18 inches Leg opening: 5" but wider with zippers