Your sister approaches you with a very awkward and uncomfortable question: When you're watching porn, do you actually want the things in the porn to happen to you, or is it always mere fantasy? After catching you jerking off to what happens to be her own favorite porn video - the one with the real-life brother and sister pair fucking each other silly - she can't stop wondering. She shyly but candidly discusses the possibility of going through with this most taboo act with you. Just saying the "I word" turns her on! Sister talks herself - and you - into first getting undressed, then masturbating together. Gradually the two of you move closer to crossing that line from which you can never go back. Slowly giving into temptation, she strokes your cock, then sucks it, before finally spreading her legs and letting you into that sweet, forbidden pussy. This is a slow-burn scenario with the first ten minutes being non-nude conversational buildup for a realistic, immersive experience. By the time Sister shows you her tits, your cock will be ripping through your pants from her frequent use of your favorite trigger word!