She was naked, slouched down in the chair, with her legs spread very wide. Her left hand was squeezing one of her breasts, and occasionally pulling on...the nipple, stretching it out until her breast elongated into a cone, letting it snap back, and then repeating the process.Her right hand was busy in other areas. Right now it was rubbing her clit in a circular fashion, and her little ass seemed to be vibrating in time with her movements. After a moment, the circular motion became a vertical one,. The first thing thru my mind was that my asshole sister told on us; I blurted out before I realized it that Sue told on us didn’t she. This surprised mom and she called Sue to come in and answer a question. Sue walked in and mom asked if she knew that Charles and I were sucking each other and if she did why hadn’t she told her. Sue admitted that she had seen us together and that she was blackmailing us. Mom asked what she was getting from Charles and I; Sue came right out and told our mother. Now she was in dire straights. The urge to urinate was unbearable but she was unable to do so. I let her endure this scene while I played with her breasts, squeezing, cupping, and pinching her nipples. In no time she was pleading, saying "Please", I didn't know if she wanted to urinate or cum. I decided to allow both, but first some fun for me. I had modified a tawser, instead of a strap of leather with a slit the length to make two straps; I cut more material between them to make a wide. There is no other way to say it. I had to have her however, instead of being an asshole, I simply got up and said goodbye. Carrying the bedsheet wrapped around her body, she followed me to her door. I so wanted to rip off that bedsheet and see her naked again but I didn’t. I think she knew it too. nothing happened as she opened the door and saw me out. I headed home and she went back to her bed to lay down she told me later on. However, what happened later that day was something she wasn’t too.