I think it might involve themes like exploration of personal boundaries or seeking new forms of pleasure. But it's important to note that such content can be quite sensitive and not suitable for all audiences.
It's more likely a stereotype. In college, girls have diverse interests and personalities. Generalizing that some have a particular preference like this is unfair and inaccurate. Most college students are focused on their studies, socializing in healthy ways, and exploring various aspects of life other than such specific and inappropriate topics.
I'm not sure if they are common. It's a rather personal and unexpected situation that may not be openly discussed often. Some might occur due to miscommunication or in the heat of the moment in a sexual encounter. But overall, it's hard to say how common it really is.
Well, pain in anal sex might occur when there's not enough communication between partners. If the penetrating partner is too forceful without considering the other's feelings, it can cause pain. Additionally, for those new to anal sex, the body may not be accustomed to the sensation yet, which often results in pain. It's crucial to start slow and gradually increase the intensity if both parties are comfortable with it.
Sharing such personal and private experiences like 'anal stories' is not ethical. These are very intimate aspects of a person's life and should be kept private. It also violates the privacy and dignity of those involved.