some years ago, I was living with a woman called Sharon, and we often liked to do this on the living room sofa in the evening....One evening, she was face down like this and I was thrusting on top behind her, both of us naked, when I noticed a slight movement from the doorway....the door was ajar slightly, and my heart leapt when I saw her daughter carefully peeking in around the door at us.....my cock tensed, and I thrusted faster, making Sharon gasp and groan louder......Her daughter was gazing at us with her mouth open a little as she seemed to be panting softly, and I could just see her right arm was moving a little and I realised she had her hand between her thighs and was rubbing over her pink pyjama leggings!