You're hanging in your room when your little sister storms in. She's visibly upset when she plops down on your bed and tells you she's had the worst day at school. You both know your mom isn't the best person to talk to about these kinds of things so you offer a listening ear. The popular girls have been making fun of her lately, she tells you. Especially in the locker room where it's apparently obvious that your little sis has more curves now then those girls ever will. You ask what's going on with them and she admits that they told her she has a fat ass. You can't help but laugh at the situation, especially because you know those girls are only doing this to your sister because they're jealous. You assure your sis that guys love fat asses, even you and all your friends do. This perks her up, and now she's trying not to blush in front of you. She doesn't believe you, but you assure her that her ass is perfect. Actually, it's beyond perfect. As you're sitting with your sister and thinking of her tight round ass in those little shorts she has on you can't help but get a little hard. Too bad your sister immediately notices and points out that you look happy to see her. She's flattered that you actually find her attractive and suggests maybe she pay you back for cheering her up. Before you can ask her what she has in mind she's inviting you to get a closer look at her ass. You know it's wrong but if she's going to taunt you like that you can't resist. She shows off her big perfect booty in the pair of jean shorts you throb over, and as you begin stroking yourself to your sister twerking and showing off she offers to take things even further! No way. Staring at her and touching yourself is one thing, but sex?! With your sister?! On the other hand, when will you get this opportunity ever again? She pushes you down on the bed and demands you let her take control. You're not going to argue with that, so you let her work her magic on your dick. She slides you in reverse cowgirl and immediately you watch her ass bounce up and down as your cock stretches her tight young pussy. She's got you aching to explode when she encourages you to bend her over and show her what you've got. You waste no time pushing her head into the carpet with her ass arched nice and high - ready for your throbbing dick. You slip inside her and pound her as fast and hard as you can. You're about to pull out and cum on her ass when she BEGS you to fill up her pussy and creampie her. Without thinking you shoot a nice big load of spunk right inside her little pussy. You ought to cheer her up more often!