You invite your stepsister over to you and your wife's house for dinner. When she arrives, she immediately is thrilled to see you, but ignores and kind of passively is a bitch to your wife. She says it is just to protect you, but you know your stepsister better. She makes snide remarks about her cooking and fawns over you the whole time. When they all start playing a card game to end the night, the wife gets tired, and your stepsister tells her to go to bed if she needs to, but you and your big stepsis are going to catch up more. She goes to bed, leaving you two alone. She asks how you are doing, and if she is taking care of you properly. She knows no one can take care of you like your big stepsister can... Especially after all you two used to do together. She knows it is wrong, but she knows how badly you miss her too, and all she wants is to feel and please her lil step-bro like she used to. She mounts you, and she grinds and rides you until you can't help but cum inside of her. She doesn't care, she wants you, all of you. You belong to your big stepsis and always have. Let's hope your wife didn't hear any of that...