No, it is not appropriate. Fanfiction often has a wide audience, including minors, and such explicit sexual content is not suitable for general consumption.
No. Anal sex in public is not legal in most places. Public sexual activities are considered inappropriate and violate public decency laws. These laws are in place to maintain a proper and respectful public environment.
Yes, there are many fanfictions that focus on their friendship or adventures together in a non - sexual way. For example, some might explore how they team up to solve a mystery in the Doctor Who universe. These fanfictions can be found on various fanfiction websites by using the right search filters.
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.