What your wife likes might be considered a bit unusual in a general sense. However, different people have different levels of comfort with their bodies. As long as it is within the boundaries of a private and consensual relationship, it could be seen as a personal preference. But it's also important to ensure that it doesn't violate any social or family norms.
This type of content is not suitable for literature because it can be offensive to many readers. Literature should be a platform for positive ideas, creativity, and cultural expression. A story with such a theme may also be rejected by publishers and readers alike due to its inappropriate nature.
No. Comparing in such a vulgar way is inappropriate and not acceptable in civilized society. It violates the norms of good taste and respect for others.
This kind of interest is not in line with the norms of a healthy relationship. A good marriage relationship should be built on positive emotions, common goals and positive communication. You can try to introduce some positive literary works or movies to your wife to guide her interests to a more positive direction.
There was this time when we were having a picnic. I had made a homemade pizza. My wife started eating it and she loved how the crust was crispy on the outside and soft on the inside. She ended up eating most of it while chatting about how good it was.
Most mainstream movies avoid such explicit and disturbing content. The movie industry generally adheres to certain moral and ethical standards, and such a plot would be considered inappropriate and offensive for a wide audience. However, in some very low - budget or underground movies that are not subject to the usual regulations, there might be some extremely rare and inappropriate depictions, but these are not the norm.