I'm not sure specifically as I haven't read this particular fanfic. But generally, in a Naruto fanfic with a harem jutsu theme, it might involve Naruto using his harem jutsu in new and unexpected ways, perhaps in some sort of adventure where his unique jutsu plays a key role in interactions with other characters.
Since 'lemon' implies adult - related content, which is not something that is widely promoted or considered appropriate in the Naruto fanfic community. For regular Naruto x harem jutsu fanfics, popularity can vary. Some might be popular because they explore Naruto's character development in a new light, like showing how he matures in handling relationships with his peers while using the harem jutsu in creative ways during battles or missions.
One idea could be a fanfic where a young ninja discovers a unique way to combine lightning jutsu with other elements like water, creating a new and powerful technique. This could lead to him being sought after by different clans for his knowledge.
In some fanfictions, the Harem Jutsu plotline involves Naruto accidentally using it on a group of powerful female ninja who then become obsessed with him. This leads to all sorts of chaos as Naruto tries to figure out how to reverse the effects while also dealing with the newfound attention. And there are also fanfictions where the Harem Jutsu is enhanced by some magical or mysterious force, making it even more powerful and unpredictable.
In addition to Sakura and Hinata, characters like Ino might be included. Ino is Naruto's friend and has her own charm. Also, Tenten could be part of it. She is a strong - willed character and could add an interesting dynamic to the harem. And sometimes even female characters from other villages might be added to the harem in fanfiction, like Temari. This broadens the scope of the relationships and interactions in the fan - created story.
A third idea for a Naruto poison jutsu fanfic could be a story set in a different era of the Naruto universe. In this time, poison jutsu is a highly respected and feared art. A young ninja, inspired by tales of Naruto, tries to master poison jutsu. However, they face many challenges, including a corrupt master who wants to use the ninja's skills for evil. The young ninja must then decide whether to follow the master or break away and use their skills for the greater good.
A fanfic could also explore Naruto using the Smoke Jutsu for a rescue mission. Suppose some of his friends are trapped in a building surrounded by enemies. Naruto uses the Smoke Jutsu to cover the area. The smoke is so thick that the enemies can't see. Then he sneaks into the building, rescues his friends, and they all escape under the cover of the remaining smoke.
Definitely Naruto has to be at the center. But aside from the obvious ones like Sakura and Hinata, characters like Anko Mitarashi can also be part of the story. She has a unique personality that can add a lot of spice to the harem jutsu - related plot. Also, Kurenai Yuhi could be involved. Her calm and composed nature contrasts with the chaos that the Harem Jutsu can bring. And don't forget about Karin, who has her own history with Naruto and could be an interesting addition to the harem in fanfiction.
Well, perhaps a plot where the harem no jutsu is used not just for comical effect but to actually solve a complex political situation in the Naruto world. The various characters in the 'harem' could use their unique skills and influence to bring about peace. It could also be interesting to see how Naruto manages this new dynamic among the characters in his 'harem' and how it changes his relationships with them on a deeper level.
One common theme is the discovery of new sealing jutsu. Writers often create new and powerful sealing techniques for their characters to find or develop. Another theme is the power struggle related to sealing jutsu. Since they can be used to seal away great power or even demons, there's often a fight over who controls them.