Sister's prank went too far, she wants my cock.. I'm fine with it

A young woman in a dark t-shirt and white socks sits on a gray couch, reading while adjusting her underwear. A hand applies lubricant to her lower back and hips as she leans forward. She then straddles a man on the couch, grinding against him as he holds her hips. The scene shows close physical contact and movement consistent with sexual activity, with no explicit penetration visible in the provided frames.