You are video chatting with your big sister, who is away at college. She tells you that she has to get ready to go on a date and says goodbye - but she forgets to end the call properly and you get a good eyeful as she changes out of her casual t-shirt and shorts and into a slinky, sequined cocktail dress. As she finishes changing she finally notices that you're still there. Your big sis freaks out, berating you for spying on her and not saying anything. Then she notices the look on your face - it's the exact same look you've had every time she's walked in on you while you were jerking off! She accuses you of whacking off to her and demands that you point the camera down, revealing your hard cock. Big Sis teases you, mocking you for the fact that you were jerking off to your own sister, telling you what a pervert and weirdo you are while still teasing you with her body. As she gets into it, she starts telling you about what a slut she's become in college and how much she likes getting guys off. She likes it so much that she'll even help you get off, her own brother. She takes her tits out and encourages you to stroke for her as she plays with her nipples up close to the camera. You'd better be quick about it, because your slutty sister has a hot date to get to. She gives you a cum countdown, demanding to see her younger brother cum, before dissolving into hysterical giggles and hanging up when you do.