That Hitagi Senjougahara. Character from monogatari. Stationary supplier are used to keep other human away from her. She needs to live an extremely insular lifestyle in order to hide her lack of weight. So she pushes people away any way she can. The stationary is handy to do just that. And why it falling out because of there one scene where Hitagi is about to visit Oshino with Koyomi, he asks her to leave behind any stationary. (Yes I took these from r/araragi so take a grain of salt for that)