I love how everyone likes teasing Nononon lol
As someone who was a lot like her (in mainly the naive/self confidence issues way) I can say that my friends, at least, seemed to find the temptation to tease me irresistible for some reason. They did it so much that by the time I was in college my innocence regarding all aspects of innuendo and such (which was what I was lacking in knowledge on that they mainly teased me for) was essentially gone. (I still blush crazy easily though- unfortunately that bit never changed.)
That said, it'd be interesting to see Yumimi react to other people teasing Nononon- I feel like it's almost her love language with her.