Maybe you're not 100% sure which styles and fits — flared, skinny, bootcut, etcetera — are going to give your rear the most bang for its buck. Well, school is officially in session: We enlisted denim-fit experts from DL1961 Mother , and Paige to break down six common butt types and the best pairs of jeans to shop for each. Click ahead for the ultimate guide. Bum's the word.