I was only eighteen and spending the summer working at my father's factory before going to university when I had my first experience in the joys of incestuous sex. I was the only male working there, apart from my father who never seemed to leave his office, so when it cam to toilet facilities there was one large area shared by everyone. I had already been teased mercilessly by the women working there so I always made sure they were busy on their machines before I ventured into the loo.
As I sneaked in one day I heard noises coming from the middle of the three cubicles but I was surprised as all the machinists were hard at work. The noises I heard, however, didn't sound like someone relieving themselves, at least not in the way you usually do in a toilet. What I heard was a kind of "slurping" sound as though someone was enthusiastically sucking on something -- and whatever it was, someone else was really enjoying it.
"Yes, you slut, suck it, suck it deep. Take it all, take all I've got."
I may be only eighteen but I now knew what was going on. The voice coming from the central stall was Bill, our delivery driver. What I didn't know was who was giving him so much pleasure. Every one of the girls was accounted for, so I thought, but I had forgotten about one.
As I crept silently into the adjoining cubicle, I climbed on to the toilet and looked over onto my first live sex show. Bill was now pistoning his hips hard and fast, his thick cock sliding easily down the hungry throat of -- my twin sister! She was also helping out in the factory over the summer but I thought she was busy with Mum and Dad in the office. She was certainly busy.
Bills overalls were wrapped around his ankles as Dawn swallowed his throbbing penis with all the experience of a porn star and I suddenly realised this was not the first time she had satisfied a man in this way. Her jeans were also around her ankles, her pink cotton knickers too, and her hand was rubbing her pussy just as hard and as fast as Bill was hammering her mouth.
I was torn between watching my sister giving her energetic blowjob and pulling out my own aroused cock and joining in the fun secretly. But then a better idea began to form in my innocent, twisted mind. I would have loved to have seen Bill cum all over her face or to see her swallow his spunk but instead I very quietly took out my phone and switched it to video mode. Making sure I had both of them in the shot, I coughed and said, "Hi, sis."
By their reaction you'd think that they had just been shot as both looked up in fright then struggled to somehow hide what they had been doing. Bill was the first to recover but he had great difficulty trying to force his still rampant cock into his overalls; he simply pushed Dawn out of his way and fled out the door as if he was being chased by the Devil himself.
"What the hell do you think you're playing at?" Dawn demanded, trying to act cool but it's hard to keep up that pretence when you're trying to raise yourself off the toilet floor, your tight jeans and wet knickers still around your ankles and your twin brother staring at your bald, dripping cunt. "I could ask you the same question," I replied, still looking down at her from my perch, "But I think the answer is quite obvious. I think Mum and Dad will love this video."
"You wouldn't dare," she tried to bluster, now back on her feet and pulling up her knickers and jeans.
"Oh I would, in fact I will, unless you do something for me."
"What do you want, you creep?" She was terrified of our parents finding out what she had been up to but now she could see some glimmer of a reprieve.
"Nothing much," I replied, my turn to be cool now. "I'll just ask for the same that Bill was getting. I'll let you be the one to give me my first blowjob."
"What? No! Never! Never in a million years!"
"Ok, then, I'll just pop up to the office and let Mum and Dad enjoy the show."
Dawn tried to think for a minute. After all, she did enjoy giving blowjobs and one cock was pretty much like any other when it was worming down your throat.
"All right, get in here, you sick prick."
I couldn't move fast enough as I bolted out of one cubicle and into the next. Dawn moved aside to let me in and then locked the door behind her. I sat down on the toilet and opened my overalls all the way down to where my cock was straining to get out. I don't think I'm anything extraordinary when it comes to length but I don't think I've ever been bigger or harder than I was then watching my twin sister get into position.
"Just a minute, Dawn, I think I need you to be naked."
"Oh, for God's sake! Is there anything else before I can do for your highness?"
"No, I think a blowjob from my naked twin sister should just about do it," I smiled pleasantly.
Dawn hesitated for just a moment but, as I started to watch her earlier performance with Bill on my phone and she could hear the noises they were both making, she relented and started to rapidly tug open the buttons on her plain white blouse.
"Hey, take it easy. I want to enjoy this."
