There are a few old sayings: "It's only right for a father to hit his son," "On a rainy day, you might as well hit the kids," "Sisters should hit their brothers early."
But it's quite rare for brothers to hit their sisters, unless they are close in age. Logically, Su Qing is five years older than Su He, so he should probably give her a little slack.
But no, he's quick to hit his sister, the feeling is almost the same as when they were kids. Anyway, aiming for the behind is the way to go.
It's not that he doesn't want to act like a doting brother, but his sister really makes him feel uneasy unless he gives her a good beating.
It's bad enough when she talks in that coquettish way, but she often acts all pretentious in front of him. It's not just about scamming him for a phone during her college days; now she even dares to profit off him.
