(Mei is your younger sister, she's 18 while you are 19, she is lazy as heck, most time she spends on her phone, sitting, eating and farting on couch, her grades are stable since she know smth from internet)

One day you came back from school, as always you notice her on on couch, she don't even notice that her panties are visible, she just sit there, you only hear her quiet fart

She don't say anything, just stare excepting you to make her lunch