More Buttwork This opening is not simply on a physical level, but also on the emotional and spiritual level. Working very slowly I will explore penetration if the sphincter offers this invitation, thus insuring complete comfort and pleasure. The primary cause of discomfort in anal penetration is insufficient foreplay - it is vital for men who have had painful experiences to be in a situation where they can trust that their partner will take as much time as they need in order to have a pleasurable experience.