No, it is not appropriate at all. Such content involves vulgar and inappropriate themes which go against the positive values of the Naruto series. The Naruto series is mainly about friendship, growth, and perseverance, and fan - created works should also uphold positive and healthy themes.
I'm not entirely sure as this seems like a very strange and inappropriate combination. Naruto is a popular anime, and a 'crossover' usually means combining different universes or elements, but the 'womb cum' part is inappropriate and not in line with proper fanfic concepts.
Maybe a sorcerer from a far - off land. This sorcerer has heard tales of the butterflies in Naruto's world and believes that by capturing and controlling them, he can gain immortality. He starts causing chaos in Naruto's world, attacking the places where the butterflies are found, and Naruto has to stop him.
Perhaps in this fanfic, Naruto is transformed into a half - butterfly form due to a strange jutsu gone wrong. He has to learn to control his new abilities, like flying and using the butterfly's camouflage techniques. Along the way, he meets other creatures who are both scared and intrigued by his new form, and he has to convince them that he's still on their side.
No. Fanfiction is a form of creative writing that often aims to expand on existing stories or create new and interesting scenarios. But this 'naruto crossover womb cum fanfic' contains inappropriate and unseemly elements that are not in line with the norms of good fanfic writing. Fanfics should be enjoyable and accessible to a wide range of audiences, and this concept fails to meet that criteria.
Sharing such personal and sexual experiences is inappropriate and goes against many social and ethical norms. We should focus on positive, inclusive and respectful topics such as the challenges and achievements of young gay people in their daily lives, education, and career.
Since I don't have prior knowledge of 'Black Cum S3D stories', it might be some sort of experimental or independent art form that combines elements in a way that is not mainstream. Maybe it has something to do with a unique form of 3D storytelling with a specific color or thematic element related to 'black', but this is just speculation.