Galavauntieing
A galavanter who's so eager to be your auntie that she'll even try to be your auntie by pretending to be your mom's best friend, even if she's not.
My neighbor tried to be my auntie by saying she was my mom's best friend. My mom didn't believe her.
My cousin tried to be my auntie by telling my mom lies. She got caught.
My friend tried to be my auntie by stealing my mom's phone. It didn't work.