“What’s that?” one of my classmates asked.“The fourth dimensional analog of a cube,” I responded automatically. Everyone looked at me. “Uh...... I don’t know what it looks like,” I said. “Madeleine l’Engle talks about it in her book A Wrinkle in Time. I read all her books when I was in sixth grade.” In fact, I was anxious to read it to the boys when they were a little older.“O-kay,” my classmate said.“That’s all the information you need,” Doc said. “A fourth dimensional cube. How do you represent. .Some students wants to take more than one lesson per day…other take just one..” I said as she pressed my second finger against her butt-hole. For some-one being tied up, she seemed pretty much in control of things. As two fingers slowly penetrated her, I softly bit her nipple. Just to feel its hardness. And also, possibly to show her who was in charge, should she had forgotten. I looked up at her. Her eyes were closed, but there was a hint of a smile on her lips. “There is still 51 minutes. “You really don’t need to be particularly skilled at acting or anything. All you’ve got to do is like sex. I mean, you enjoy fucking don’t you?” “Well, of course!” laughed Amna who’d never had any sexual encounter with anyone. She’d never really considered it, and she’d always thought it was one of those things that only became possible when one left the protective embrace of the family. On the other hand, the idea clearly excited her as testified by the warm heat rising from between her legs. “I’m sorry,” I said without thinking.She sighed, shaking her head as she stood up. At first, I thought she was going to walk away, but instead she moved behind me slightly to sit down in the small space I’d left from sitting up. I quickly shifted my weight to sit beside her on the couch, me still mostly naked, while she was only wearing the leather jacket.She seemed pensive now.“Please say something,” I whispered after a second. Part of me still wanted to try denying it, but for whatever reason.