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."
I sat there on the toilet, playing with my cock, slowly moving my hand up and down as my twin sister did a striptease not two feet away. When her blouse was open she simply shrugged it off her shoulders and, for the very first time, I saw my sister's pert tits encased in her pink, lacy bra.
"Now the bra," I ordered, enjoying the sight of her tits and the sight of her red, embarrassed face.
She reached around, opened the clasp and the pink material feel down her arms and onto the floor. She tried to hide her tiny breasts behind her hands but, on hearing my recording again, she reached down and started to open the button on the waistband of her jeans. As she leaned forward to pull her jeans off her face was almost touching my prick in the tight, confined space but she quickly reared up and stood in only her matching pink knickers.
"I'll take those," I offered as she was about to drop them on the pile of clothes on the floor. She threw them at me I caught them in my left hand, my right being too busy playing with my cock. I brought them to my nose and inhaled -- deeply.
"You really are a sick pervert," Dawn growled but I was in another world. I could smell the musky aroma of my twin sister's pussy on her kickers and I was about to feel her soft lips wrapped around my aching cock.
Dawn knelt down between my outstretched legs and opened her mouth. She opened her lips and let me slide into her warm, wet mouth. The feel of my hard cock against her tongue was everything I had imagined. Dawn swirled her tongue over the swollen tip and used it to explore the length of my cock. When I felt my dick push against the back of her mouth, Dawn used skills I never knew she had and let my cock slide down her throat.
I thought I would have to press her head down but she continued to aggressively lick and suck my cock. She obviously loved what she was doing and was good at it. I sat back and let it happen.
But I wasn't the only one enjoying myself. I could see that Dawn had slipped two fingers into her pussy and was using the palm of her hand to rub her inflamed clit.
Her cock-sucking skills were so good that I could feel my balls quickly filling with cum. Dawn's head bobbed aggressively up and down the length of his cock and I wasn't going to be able to take much more. Just as I was about to explode, I did put my hand on the back of her head and thrust deep into her mouth. My cum exploded into her mouth again and again and I watched it drip from her small mouth.
"So what exactly is going on here?" asked a voice from above.
I looked up, terrified, because I knew that voice.
"It's not what you think, Mum," I tried to explain.