hi annon
if what you describe of the situation is an accurate accounting, you can work on forgiving yourself. it does not seem that your sister was the object of a malicious act. you were not looking to get gratification from her. it was a supermodel you were kissing. the level of disgust you are feeling is not necessary for what you have stated as simple pecks. you are accurate in having taken advantage of her so i can understand your shame and guilt. this is something you may need some assistance working through.

welcome to psych central. you will find we have several forums where you can post about your concerns and receive feedback from other members. you will get a lot of support here. again, welcome