Sistager

It derives from "sister" and "manager". It refers to a sister who servers as a manager to her siblings.

A sistager will tell you exactly what to wear and how to speak.
My sistager answers calls on my behalf.

Sistager by Lebanesegov September 9, 2022

sistagirl 

Usually in reference to another Black female (from a Black female). Rarely used to refer to white women.
Another term for sister or sistah.

The name of Undercover Brother's sidekick and love interest in "Undercover Brother" (starring Eddie Griffin).

"Sistagirl, those boots are slammin'!"

sistagirl by solitaire8868 July 3, 2006

sistacer 

a sister eraser duh

Hey sister can you snatch me that sistacer
yeah sure sister

sistacer by Sister snatched July 26, 2018