Some say that there are only two types of people in this world: those who are interested in anal play, and those who haven’t tried it yet. Whether this is true or not, people having fun back there is a simple question of anatomy. Our anal sphincters (muscle surrounding the rectum) are full of nerve endings, and to us (humans), it feels good when our nerves are messed with. But, a lot of people are doubtful when it comes to making that first step you never go back from. Do you need medical advice? Why does it sometimes feel painful? What should you start with?