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.
In fanfic, 'breast expansion' is a fictional concept often used in certain types of fan - created stories where a character's breasts grow or expand in an exaggerated way. However, 'dick growth' is also a rather strange and inappropriate concept in this context. Fanfic often explores various out - of - the - ordinary or fantasy - like scenarios, but these can be quite extreme and not suitable for all audiences.
One common theme is the exploration of body transformation in a fictional and often fantastical way. It might involve characters experiencing unexpected or magical growth. Another theme could be the psychological impact on the characters, such as how they deal with the sudden change in their appearance. Also, sometimes it's related to the idea of self - acceptance or the reactions of others in the fictional world to this new physical state.
Well, often there's a sense of the extraordinary or the abnormal in these stories. It's not something that occurs in normal life, so it plays on the idea of the out - of - the - ordinary. Also, these stories may deal with how society views those with such extreme physical characteristics. Like, are they feared, worshipped, or something else? And the breast expansion can be a part of the overall physical transformation that serves to make the characters more distinct and, in some ways, more powerful.
Well, one common theme could be body transformation. It might explore how a character's body changes in a fantastical way related to breast expansion. Another theme could be the psychological impact on the character experiencing such a change, like dealing with newfound attention or self - image issues.
Writing about such 'breast expansion sexy fanfic' involves inappropriate and unethical content, so I cannot provide relevant information on this.
One common theme could be self - discovery. The characters might be exploring new aspects of their identity as they experience physical changes like breast expansion. Another theme could be power dynamics. For example, the new physical form might change how they are perceived in society within the fictional world, giving them more or less power in different situations. And also there could be themes related to acceptance, both of oneself and by others, as the characters deal with their altered bodies.
One common theme is the use of magical or scientific elements. For example, a character might come across a potion or a new technology that causes breast growth. Another theme could be self - discovery. The character might experience breast growth and then have to deal with how it changes their self - image and how they interact with others. Also, some breast growth fanfic might involve a transformation journey, where the growth is part of a larger physical or emotional change.
One common theme is the element of surprise or accident. Often, breast expansion is not something the character desires or anticipates, like in a magic - gone - wrong scenario.
I can't really say for sure as this is a rather unusual and not so mainstream topic. But perhaps if there are any, it might involve some sort of body modification within the context of the Undertale universe, which could be very different from the normal themes in Undertale like friendship and self - discovery.
I'm sorry, but these topics often involve inappropriate and vulgar content, so I can't provide relevant answers.