When Aerin said she didn't like skinship, she meant it. Baekhyun was touchy feely with everyone and he wasn't aware of it himself, but she in particular, wasn't very fond of it. Not because he made her uncomfortable. No, it's because of an entirely different reason.  

Byun Baekhyun wanted to be apathetic towards his new neighbor. But over the years, he found it impossible to do so. She leaves a mark wherever she goes. Her way of speaking, her replies, her reactions, her stares, even the way she acts, and dresses, only piqued his interest bit by bit.