I was recently "giving her stuff i don't need", which was Burgers left from the last Event, Elixirs and Sexual Energy Drinks that i never use anyway, Radars (since i thought they'll disapear just like Burgers at teh start of EG event), 3 unused Coliseum Gacha Tickets form the last Coliseum Event, plus someextra stuff like Candies and 10 Ngacha Tickets and 10 N Wild Cards when i had not enough of said "unneeded items" to fill all 4 slots. Got alot of SR Wilds back (at least one every time), R wilds, R Gacha and, surprisingly, the N Special Girl Card.
So i have an idea: maybe N Gacha Tickets and N WildCards are good for getting N Girls? Kinda like if you say something like: "Hey Curito, i like you and i think you are more lucky and experienced in all this gacha-like stuff than me - go roll that Gacha with these tickets for me" by giving her the Gacha Tickets. And wildcards are, again, a reference to what you want to get - a new card to level-up - kinda if you have nothing to invest those extra WildCards into.

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Update: spamming her with 1 R Gacha Ticket + 10 N Gacha Tickets + 10 N WildCards + 10 Candies or 1 R Gacha Ticket + some Elixirs and some Sexual Energy Drinks gave me around 3 N Limited cards and 2 R limited cards. Spamming 2 and 3 R Gacha Tickets alone or with same stuff as above gave me only different Wildcards and Peronamin. So, i guess, i'll stick to 1 R Gacha or 1 R Gacha + Elixirs/Sexdrinks/Candies or that + 10 N Wildcards, since they are of very little use and i get them alot, while i still use N Gacha Tickets everyday to complete Daily Mission and get an extra SR WC.

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Update. I guess my theory is true, because today i got 2 more N Girls by giving Curito 2 Rgacha Tickets + 10 Candies + 10 N Gacha Tickets + 10 N WildCards. (a tip for those of you who can't get the N girl and think it is the hardest to get)
If someone wish, you can try adding 10 R WildCards to 1 or 2 R Gacha and see if it will result in getting R Girl card, or experiment with some R Gacha + SR Wildcards to see if it will result in getting the SR Girl. ( have too little of them to test that)
Still, i don't think 1 R Gacha is a good way fo getting SR girl, since i have waster around 40 already, and still, no SR girl.
Not even sure that 2 or 3 is a good way, because i've tried that and got nothing.
Thinking of it more, i guess i'd rather give her tons of good stuff at once, than spamming her even more over time.