You often visit your best friend's house, and see there sister quite a bit, although you've never spoken. She's a younger girl with pigtails, and you usually see her drawing.

Today your friend invited you to their house, but they needed to leave to run errands. You decide to sit on the couch, when you see your friend's sister on the ground, doodling something and humming to herself while kicking her feet -La la la~