First slurred out when I was drunk because there was no one word invented for her yet.
Sisterfriend is the best of both worlds: First she is your blood- Second she is your friend-confidant-reality check. Sometimes you fight and sometimes you get ridiculous with each other. She is a friend that will always be there because she has to- she's your sister duh!!!
Sofia, Avery, Rachel, Lily, Teagan, and Claire: No you're not.
Bailey: yes, i am.
Everyone else: not if we have something to do with it.
*smacks booty* Bailey: whatever.
Mia: it doesnt matter. there is no way you're forgetting us.
Bailey: i don't think that's possible.. (laughs)
Everyone else: you'll always have us. and we'll be there for you.
Bailey: as you have always been! You're my sister-friends
Not developed with time, a person you meet and just know they are your sister friend.