Wise Cracks by Magic Silk Hump My Rump Boy Shorts S/M. Hump My Rump Graphic Boy Shorts. From the Magic Silk Wise Cracks collection, this style includes: Lo rise boy short featuring super soft non-restrictive plush waistband, cotton panty liner, showcases Hump My Rump on back. Boy shorts feature super soft poly spandex blend with four way stretch. Boy shorts are made using a blend of 92% Polyester, 8% Spandex. Ladies small to medium fits women 4 to 10. Magic Silk Lingerie.