What are the common themes in dick growth hentai manga stories?

Adult stories with such themes are inappropriate and not suitable for discussion, so I can't provide relevant answers.

The common themes often revolve around intense sexual fantasies and exaggerated physical attributes for heightened arousal.

The appeal can vary from person to person. Some might find it exciting for its unique and taboo themes.

The common themes often revolve around sexual exploration and fantasy, but this type of manga is often considered inappropriate and not suitable for widespread discussion.

The common themes might include elements of surprise, power dynamics, and sometimes a focus on forbidden or taboo situations.

This kind of content is often considered inappropriate and may not be suitable for general audiences. It usually involves explicit and potentially disturbing themes.

These are not common themes. Fanfic is a vast and diverse world, with the majority of works centered around aspects like the development of the original story's world, the growth of characters in a more emotional and mental sense, and the exploration of new adventures within the given framework. Breast expansion and dick growth are not typical elements. They are more likely to be found in areas that are more about shock value or extreme and often inappropriate creativity, which is a very small part of the overall fanfic landscape.