My wife's sister pretended to have gone home and hid in the house. Then, when my sister wasn't looking, she seduced the man. However, she wasn't satisfied with just one sex session, and she escalated it to "in the closet!", "hiding in a cardboard box!", "on the bed after sleep!", etc., even though my sister was nearby. If she was found out, both the relationship between husband and wife and the relationship between sisters would fall apart in an instant! I'm so excited about the "continuous cuckold sex" at such close ranges!