This is an idea have in mind
Naruto x kaguya (or harem if you want but I want kaguya at the main woman)
Make naruto lose is virginity to kaguya at the chunin exams somewhere in the month before the tournament
Naruto is 13 year old and don't change is age when is have sex with kaguya because it would be no fun if naruto was already an adult
Kaguya don't know she immortal but she looks around 25
When Kaguya has been defeated by naruto and team seven during the fourth ninja war before she was sealed she use the last bit of her strength to use time-space ninjutsu to when naruto and team seven where they are in the forest when kaguya appeared she has one thing in her mind: kill naruto.
When after kaguya found naruto, after he was separate from his team by a strong wind jutsu . she cannot believe that this naruto was so weak compared to his older form before she kill him she observe him and waited the right moment to kill him. When after naruto was knocked unconscious by orochimaru and the rest of team was till focused on orochimaru, kaguya going to kill naruto but before the killing blow something else come in mind, in place of killing him she thinking of going to make him her slave (her sex slave too, because she remembered when the older naruto use that dirty ninjutsu, that make her so horny and that why she lost because she cannot concentrate when she in this state and later he will become her husband) she then observe him going through the exams to where kakashi don't want to train naruto because his think that sasuke need him more and he say to naruto that is weak and is always going to be weak and when kaguya see and hear that : that make her pissed off. When naruto was alone that was where kaguya make her apparitions and offer him training and if his take the training he have to going a favor for her (this where you decide to make him have sex with her on the first day or maybe after the first week).
And that about it. You can make some lemon like one or two in every chapter but the lemon must begin in chapter two or three. You can make some bashing
And you can some male character female (like )
You can make kaguya have children with but when is you to decide
If you want to make harem kaguya must be the head girl, don't add sakura, you can add older women (like kurenai, anko, yugao, shizune, tsunade or kushina (yeah I know is incest but hey she sexy and don't forget a part of her is inside naruto and kaguya can use that to revive her) you can add to the bad girls (like tayuya, konan or )
If you want to make this story so please make it come true