Your sister's friend is over wearing another skimpy outfit, you swear she does it on purpose to try and tease you. Escaping to your room with your semi hard cock you hope to find some relief but she follows you in and silently starts to paw through a book on your desk! Your mouth goes dry as she bends over, her tartan skirt lifting to reveal her big, round butt cheeks. Torn between telling her to get out so you can masturbate and wanting to savour the view she ignores you completely as you debate your dilemma. Resolving to enjoy yourself while she's distracted you just take in the sight of her huge ass peeking out from under the skirt while her hips wiggle a little to and fro. You can see she's wearing white cotton panties underneath as she bends a little lower; your favourite! Perhaps she's so engrossed she won't notice you jerking off ;)