You and your sister have been sneaking around and masturbating together every chance you get. You know it is wrong to be horny for your sister/brother so you resist the urges to fuck. The video starts with you and your sister masturbating in the kitchen together. Whoever cums first has to clean the dishes. You cum all over the floor and your mom walks back in. You almost get caught! The next morning, you are laying in bed playing with your dick next to your sister again. She brings up how hard this has been for her and that what you're doing is already (trigger word) so why not take the next step. You both knew you wouldn't be able to resist forever.