Your sister has a really dirty habit for getting gross with you. You pretend to hate it but you never stop her. She comes into your room and is all sweaty and worn out from the gym. She teases you for being in your room and all day. And then she farts on your bed and laughs. You tell her not to, and she ramps it up and farts more. She tells you she's so sweaty and gross and sticks her ass in your face, telling you her gym leggings are soaked in sweat. Get your face right in and smell her sweaty ass. She lets out more farts and takes her leggings off and shakes her ass, wafting the stink around your room. Lets get really dirty, she takes her thong off and tells you to get your tongue right in her asshole and clean up every bit of sweat and stink and dirty, like a dirty little pervert she knows you are.