Well, it could be due to a disruption in the chakra control. If the character who performed the female henge loses focus or gets distracted, the chakra maintaining the transformation might falter and cause the henge to disappear. For example, if they are suddenly attacked or startled during the henge.
One possible plot could be that Naruto accidentally uses a new type of henge that makes him disappear not just visually but also from the ninja world's chakra detection. His friends then go on a quest to find him. They might face various challenges and encounter old enemies who are taking advantage of Naruto's disappearance. In the end, they find a way to reverse the henge and bring Naruto back.
His friends would be in shock. Kakashi would take charge of the situation. He would gather all the information about what Naruto was doing before he disappeared. Naruto's friends like Choji and Ino would use their respective skills to help in the search. Ino could try to use her mind - reading jutsu on people who were around Naruto before he disappeared. They would all be determined to find Naruto because he is an important part of their team and the village.
His enemies could be thrown off - guard. If they are looking for Naruto, a male ninja, they won't expect him to be in a female form and disappear. This could give Naruto an advantage in future encounters as his enemies will be more cautious and less certain about his whereabouts. The female henge might also make some of his enemies underestimate him, thinking it's just a random girl and not realizing it's Naruto until it's too late.
One possible reason could be for stealth. By using a female henge, Naruto might be trying to blend into a group where females are less likely to be suspected. For example, if he's infiltrating an enemy base that is more vigilant against male intruders.
One possible fanfiction idea could be Naruto using his henge technique to transform into someone wearing a really cool swimsuit. Maybe he does it for a mission at a beach resort where he has to blend in with the tourists. He could transform into a famous surfer and use his skills to gather information.
One possible fanfiction could be that Naruto henge into a swimsuit as a prank. He might transform into a ridiculous swimsuit -covered version of himself to make his friends laugh. For example, he could turn into a swimsuit with a huge fish pattern all over it and start acting like a goofy mermaid in front of Sasuke and Sakura, just to break the tense mood during a training session.
Most likely not. The combination of 'panties' in the title gives the impression that it could involve inappropriate or at least very juvenile and not - so - family - friendly content. Naruto is a popular franchise that is enjoyed by a wide range of ages, and such a fanfiction concept seems to deviate from the more positive and acceptable themes usually associated with the series.
Well, Naruto could learn more about empathy. By being in Inari's form, he experiences life from Inari's perspective. This might make him more sensitive to the feelings of others who are not as confident or strong as he is.
He might also get help from his friends. For instance, Sasuke could sense that something is wrong with Naruto. With his Sharingan, Sasuke might be able to see through the henge and then use his own powers to help Naruto break free. Or Sakura could use her medical ninjutsu knowledge to somehow counter the effects of the henge on Naruto.