I just have to say I have been with my wife now for 13 years now but I have been withher sister many of time ,when my wife took showers i would fuck her sister in the hallway so i could hear the shower stop or in the kitchen as she slept..one time we fucked right infront of her and she dint know it she was outside the screen door was between us so she could not see what we were doing as I fucked her from behind had ro stop when she started moaning but played it off as a yawwn ...but we no longer have sex I got her and her friend pergnet so we no longer talk ..but my wife asked me did i fuck her sister just out of the blue ...i t think she knows .....