Her experience of not having a boyfriend is equal to her age! If that same Sumire wants to experience men once... then it has to be sex! Sumire has set the hurdle high for someone who has trouble handling men. When she asks Tachibana, who is the only man she can speak to normally, he says he'll have sex with her with some conditions.
You may feel your favorite manga should be gathered together into distinct categories for your own reference and, now, you can do this with a LIST. After you've created your list or lists, you can proudly recommend them to other manga fans to showcase and share your taste in manga.
See You In My 19th Life