He might improve it by making the transformation more dynamic. Instead of just a static form, it could have special effects like a glittery aura or flowing hair that seems to move on its own. Also, Naruto could experiment with different voices during the jutsu to make it more seductive.
He might become more confident. As he perfects the Sexy Jutsu, he has to overcome his initial shyness or hesitation. This new - found confidence could spill over into other aspects of his life, like his battles and his interactions with others.
In many fanfictions, Naruto's Sexy Jutsu serves as a comical relief. It can break the tension during intense battle scenes or serious story moments. For example, when facing a really tough opponent, Naruto uses the jutsu and the opponent's stunned reaction gives Naruto a chance to escape or plan his next move.
Well, it could be that the Sexy Jutsu has some sort of psychological effect on the Third Hokage. Maybe it reminds him of someone or something from his past that makes him hesitate. And in that moment of hesitation, Naruto is able to use the distraction to his advantage and defeat the Third Hokage. Also, Naruto might be able to use the jutsu in combination with other moves in the fanfiction. For instance, while the Third Hokage is distracted by the Sexy Jutsu, Naruto quickly follows up with a Rasengan.
Naruto might improve the Sexy Jutsu by using chakra in a more creative way. He could use it to create an illusion of a more alluring environment around him during the jutsu, like a beautiful garden or a luxurious room. This would enhance the overall effect of the jutsu.
A possible fanfiction could be one where the Kyuubi is trapped in a genjutsu created by an enemy, and Naruto uses his Sexy Jutsu to break the genjutsu. The Kyuubi, being freed, then forms a sort of pact with Naruto that involves teaching him some of its more powerful techniques in return for Naruto using his Sexy Jutsu to disrupt any future genjutsu attacks. This would be a story full of action, humor, and a unique bond between Naruto and the Kyuubi.
Well, in certain fanfic scenarios, Naruto could learn paper jutsu as a result of some experimental training. For example, he might be trying to combine different elements of his existing jutsu and accidentally discovers a way to manipulate paper. It could be that his chakra takes on a new form during a particularly intense training session and he realizes he can control paper with it.
Perhaps in the fanfiction, Naruto perfects the Sexy Jutsu to the point where it can be used for espionage. He could transform into a seductive character and infiltrate enemy strongholds, gathering valuable information without being detected. This would add a new dimension to his ninja skills.
The Sexy Jutsu adds humor by its very nature. It turns Naruto into a female form that is often overly - sexualized in a comical way. When characters react to this sudden transformation, it can create hilarious moments. For example, when an older and strict character like Kakashi sees it, his shocked or embarrassed reaction is really funny.
Most official Naruto media focuses on the battles, character development, and the overarching story of the ninja world. Fanfics that involve the 'Sexy Jutsu' in a lesbian context are likely to be a very niche and perhaps not very well - received by the general Naruto fan base as it can be seen as objectifying characters in a way that doesn't fit with the core values of the series.
To write a Naruto creates jutsu fanfiction, consider his growth as a ninja. He has learned from many mentors. In this fanfiction, he could combine the teachings of Jiraiya, Kakashi, and even the Sage of Six Paths to create a unique jutsu. For instance, he might create a jutsu that uses the Rasengan's shape - manipulation along with some of the Sage Mode's power - up. Also, don't forget the emotional aspect. Maybe he creates the jutsu in memory of a fallen comrade, giving it more significance and power.