sister tax 

when a brother causes dissatisfaction or disappointment towards a sister, so the brother must compensate for such behavior through a requested action from the sister.

mother: "go clean your room"
brother: "i'm not helping you."
sister: "sister tax, you have to clean a quarter of my room"
brother: "fine"

sister tax by hikikohardcore April 2, 2023

Sister Tax 

A percentage of your sisters money paid to you because you have to deal with her.

“Hey sis, I just got a raise!”
“Cool, where’s my sister tax?”

Sister Tax by thesedontmeananything January 10, 2020

sister food tax 

if you have a sister you are intended to have her take some food anytime she sees you or you have food.

“hey do you have food”
“Yes”
“Okay give me some, sister food tax”

sister food tax by yomama45 February 3, 2023