Maki just has a standoffish air about her. And puts up a barrier that makes it hard for people approach her, but really she's just shy and not used to interacting with others. When people do try she begins to loosen up a bit.
It's all a front, my gender-appropriate sibling. Deep beneath Umi's uptight exterior beats the heart of a freak just waiting for someone to give her permission to let it loose.
Holy shit I love this. I love how straightforward it is. I love how needy the one girl is, how she's not afraid to say it without beating around the bush, and how she is genuinely appreciative afterwards. Awesome.