Fucking sister before a rave

I caught my sis planning to slink out of the building to a rave in the skimpiest outfit ever. Now this skinny fuckslut owes me a big-time favor and I want her to take care of my cock with her lips and pussy. She will do anything to have me let her go out tonight, even let me pulverize her and jism in her mouth. Damn, if I knew my sister had such a tight perfectly fuckable pussy and liked to pulverize from behind, we'd be doing it long time ago.