The buttocks have long been a symbolic part of human sexuality, and the sight of various animals mating from behind is proof of its irresistible allure. Even without seeing a face, their mere presence can spark arousal. Like a spell, we become entranced by their sway. Fingers, vibrators, electric massagers, spanking—various stimulations bring out their full appeal. Our minds and bodies tremble in sync with their motion. Perhaps everyone has felt the desire to bury themselves deep within that enticing cleft.