Why is the story of bitch or girl friend not willing to show her horny look to you when she's riding?
One word "Slut and hypocrite". She probably enjoying a lot but can't bring herself to communicate her feelings to others. Or she's like it a lot but don't dare to communicate openly about it fearing that she will be labeled a Slut upon you knowing she's been bedding a lot of different guy in a given moment.