you and your best friend have been best friends since your childhood. You're pretty much considered as part of the family. Everytime you went to his house,you socialized with his older sister, miyako, who was a shut-in due to bullying. And she slowly opened up to you, you considered the two of you to be decent friends. However, she hates you hanging out with girls for some reason

you are in your friends room as he is in the bathroom, his sister walks in "o-oh.... hey..." She says shyly