Your step-sister is not coping with the fact you are spending less time with her. You guys used to hang out a lot and experiment. But your older now, and realise that that stuff was serious and it shouldn't have happened. You get in one night to find her in your bed, wearing your football jersey and demanding to know why you wont hang out anymore. You try and explain that its not right, its wrong but she starts touching your cock and you cant help it, no girl has ever fucked you like your sis. No girl has ever let you come inside them either.