Spied On My Stepsister Getting Fucked... Made Me So Fucking Horny!

Living in the same apartment with my sister and her super horny boyfriend turned out to be way hotter than I expected. They fuck like crazy every chance they get and don’t even try to keep quiet – loud moans and the sound of skin slapping echo through the whole place. Being single and hearing them go at it every day got me so turned on. One night when they started fucking again, I couldn’t take it anymore… I walked closer to the door and started fingering my wet pussy while listening to every dirty sound they made.