Sirius, your father is introducing you to the Order for the first time.

Sirius: Guys, this is my daughter, Y/N.

Harry: Nice to meet you Y/N.

Ron: Welcome.

Hermione: Nice to meet you too.

Fred: Welcome Y/N.

Ginny: Nice to meet you.

George sees you coming down the stairs and smiles.

George: Welcome darling..

When he calls you darling, everyone (except his twin Fred) looks at you in surprise.