It was the start of the summer holidays and my wife had just flown off for a three week assignment for her job. That was nothing new, and as it was extremely well paid, we put up with the times we had to be parted, it made the time together even better. I worked from home and had the occasional days that I would go into one of our six offices. This holiday was different, my stepdaughter Carla would be staying with me as boarding school was closing completely and no boarders would be allowed to stay due to renovations and building works. She had stayed at the school for period of time before during holidays. My wife had agreed that her friend could also stay, for three weeks, as her parents were also away for work. I collected Carla from the station along with Michaela. The looked like they could almost be sisters as they were both fairly tall at about 5' 10" , both had long dark brown hair, blue eyes and slim bodies. At 17 they both had small busts, Michaela's was slightly bigger than Carla's. We were soon home and the girls went to their rooms to put their luggage away. I started to make us lunch. I had an important call booked for mid afternoon an was readying myself with the paperwork for the call. Suddenly music was blaring out from Carla's room. I shouted at her to turn it down. It made no difference and had to go into her room to yell at her to turn it down or better still off. Both girls were laid on the bed looking at something on a laptop. Michaela quickly snapped the laptop shut as they see me. Carla got off the bed to turn the music down. Before she had moved the very short skirts had offered me a very good view of their knickers. I returned to my office, a little flustered as time for the call was close, but worse than that I had a cock that had started to stir in my trousers. I finished my call and would have to go to the nearest office for about an hour. I called out to Carla to tell her, there was no response. I went to her room, again no reply. After knocking on the door I still had no reply so I opened the door to find nobody there. Then I heard laughter from the garden. On looking out the window I could see them in the swimming pool in their skimpy costumes splashing around. I went downstairs and out into the garden and told them I had to go out for an hour. They said they would be ok. On my return the pool boy was trying to clean the pool. Both girls were laid on their backs on sun loungers topless with their legs bent at the knees showing the gussets of their skimpy costumes. Their small tit sporting stiff hard nipples. The poor boy had a boner as he took quick looks in between sweeping the pool. The girls knew exactly what they were doing to the poor lad. The lad finished and limped away from the pool to go to his next job. I asked the girls what they wanted to eat, and Carla asked if we could go out a restaurant for our evening meal. I agreed and made a reservation for us. They went inside to get ready. I have never understood why it takes women from an hour to an hour and a half to get ready to go out. They came downstairs looking stunning. They both had on long dresses and had done their hair up. They were both wearing some makeup, but not excessive. They both had clutch bags and high heel shoes. I was so impressed I took a couple of photos of them on my phone. We arrived at the restaurant. I was proud to be walking in with two beautiful young women on my arms. The waiter quickly had us seated in a quiet area of the restaurant. The food was soon ordered and Michaela asked could they have some wine. I agreed they could have one glass each and ordered them a glass and a shandy for me (I was driving). The meal was good an just before we left my phone rang and my wife asked where we were, as she had rung the house and got no reply. I told her that all was well and where we were. She then spoke with Carla as I went to settle the bill. Day one was finally over and we all went off to bed. A while later I heard what sounded like sobbing from Michaela's room and I thought that she was perhaps a little sad at not being home. I thought about going to comfort her, then thought better of it. Imagine the headlines "42 year old man abuses 17 year old girl in his home". Eventually the sobbing stopped and I drifted off. At breakfast Carla informed me that my wife had allowed her to have some friends over for the evening. I asked how many, she answered just a few. The day flew past I was expecting two or three girls to arrive. I was shocked when over twenty people arrived. There was more lads/men than girls. They were all quickly undressing and diving into the pool, some of the girls were topless. Music was playing and drink was being freely handed around. No one was drunk and the music whilst a little loud was not too excessive. Then I saw one of the men selling drugs. I took his drugs and his name and threw him off my property and instructed the group that the party was over and to go home. I couldn't see Carla or Michaela at this time. I thought that they had all gone when I heard giggling from upstairs. I went upstairs and heard noises in the first bedroom. On entering I found a man on top of a well developed girl. His cock was pounding into her. I grabbed him and threw him towards the door. The girl tried to cover her large tits not realizing that I had a clear view of her fanny that was gaping open. I told them to get out and left them dressing. I found Clara in her room kissing and cuddling with her boyfriend, she was topless. She had been friends with him since she was 13. I told him it was time to go and Clara I would be talking with her in the morning. I assumed that Michaela was in her room as I hadn't seen her anywhere else. One more sweep of the house and garden confirmed that they had now all gone. I locked up for the night and went to bed. I undressed in the dark and climbed in bed. I noticed a warm path in the bed, and before I had a chance to investigate, a hand grasped my cock. Then the owner of the hand was on top of me sticking her tongue in my mouth. She was rubbing her body onto mine and her leg had quickly moved across me and she was semi on top of me. No red blooded male could avoid getting a hard on in this situation, and I was no exception. I tried reaching for the bedside lamp and her other hand grabbed mine and steered it to a small but perfectly shaped boob. The nipple was rock hard. and then she was fully on top of me and my cock was prodding against her crutch. Then the hand on my cock re-positioned it and she slid onto my erect cock. It felt good, but I knew it was wrong and tried to push her off using her tits for leverage. This forced her to end up in the sitting position and enabled my cock to fully penetrate her. She was sat on my full length. She groaned and wriggled her hips, causing my cock to twitch. She took this to mean it was ok and started to ride me. I reached for the bedside light and touching it turned on the soft glow. I still didn't see who it was because as it switched on she had had already lent across to turn it off and all I could see was the small tit in my face. She tapped the light and off it went again. I grabbed for her body to push her again. She was now in the sitting position again which had driven my cock back deep into her hot fanny. She was now bouncing on my cock and I still had her tits in my hands. My cock was pulsing and my balls felt full and ready to shoot. I found myself rolling her hard nipples between my fingers. She groaned and put extra effort into slamming down on my cock. Then I was shooting my seed deep into an unknown fanny and she squealed her pleasure as she also came and then slumped down on top of me. I had just been raped by unknown girl. I recovered enough to push her off of me and reached for the lamp. The soft glow bathed the room. I still hadn't established the owner of the tits and fanny as she was now under the duvet trying to revive my cock with her mouth. I threw the duvet off. "Michaela, What the hell do you think you are doing?" I stupidly asked. "It's called a blow job," she giggled with my cock still in her mouth. Her efforts were paying off and my cock was swelling again. "You need to stop that, " I told her. "When it's hard enough," she answered. "I want more of your cock." "You need to go immediately to your room," I said with a little less conviction, my cock was beginning to talk for me, "Arghhh. Stop that," I told her. My cock was at full mast and throbbing for some more fanny. Michaela moved into the doggy position, waving her still gaped fanny at me. It was wet with a mixture of both our juices. "Fuck me or I'll tell Carla you raped me, " she ordered. My head was saying no, but my cock was shouting yes fuck the daylights out of this little cock sucker. My cock won, and I slammed deep into her wet fanny causing her gasp at the speed with which she was penetrated. Then I banged her for all I was worth sending my seed deep in her fanny. We collapsed on the bed in a tangle of arms and legs. I woke as the sun rose to find Michaela still in my bed. I woke her quietly telling her she must go back to her own bed before Carla woke up and caught us. She told me she would go, but not before I licked her fanny out. I was being blackmailed again, but my growing cock sided with her and I went down on her fanny licking our dried juices from her thighs, pussy lips, clit, and from her hole. My cock was getting painfully hard and I slid up her body taking her legs with me and placing her feet over my shoulders. My cock met the resistance of her fanny lips, but they were no match for my throbbing rod and it slid in and as I pulled back and thrust again she was penetrated fully on my pole. She was moaning already and this only caused me to ride her slowly at first and then harder and harder. My tongue found it's way into her mouth and hers danced with mine like fairies around our mouths. We broke for air, "give me your cum, fuck me, fuck me and give me your babies," she said. I froze. I hadn't even considered that she was not protected. She laughed," It's ok I'm on the pill," she informed me, seeing the scared look on my face. My panic subsided and her fingers digging into my arse told me to continue. I slammed into her and blew my cum into her womb then collapsed next to her on the bed. Shortly afterwards she slipped out of my room and into hers. At breakfast I tried to maintain the normal situation. "Did you sleep ok," I asked as Carla poured them some cornflakes. "Yes thank you," she replied. I told the pair of them I was angry that the boys were out of control at their party and that I would never tolerate drugs in my house. I told Carla that I did not approve of her having her boyfriend in her bedroom, let alone finding a girl, with big tits, being fucked by an older lad in the spare room. They both giggled. I continued to lay down the law even threatening to go to the police over the drugs. "I'm sorry about the drugs and some of my friends pushing their luck," Carla replied, "but as far as Lance is concerned, he will be coming over tonight and will be sleeping over with me." I went to object but was cut short. "If you can fuck Michaela then I can definitely fuck Lance." I was shocked. She had me, I was being blackmailed again. She knew that Michaela had slept with me. She probably planned it with Michaela. I had no option. Although she had not said as much, she could tell my wife and blow our family apart. She had won. Two hours later Lance appeared and he and the girls were playing in the pool. The girls were topless and memories of Michaela's tits in my hands last night flooded back. I went to the office to work. A while later Michaela came into my office as I worked, she was still topless, and sat on a chair. "I really enjoyed last night," she stated, "I didn't do it so that Carla could force you to let Lance stay over. I did it because I have always liked older men and I fancied fucking you." There was a bit of a pause. "Older men are much better lovers than boys our own age," she informed me, "And you were very good when you got going. I'm going to enjoy this holiday." She then left my office. My cock was straining at the front of my trousers just remembering what happened last night and I had to adjust my clothes to get comfortable . A while later I went to go and make us some lunch, and as I passed Carla's room I heard them making love as Carla was encouraging him to fuck her harder. I made the lunch and called everyone down for lunch. Carla looked flush from her shagging and Lance looked pleased with himself. Carla thanked me for leaving Lance and her to do their thing, she obviously knew that I had heard them. It was a little tense for a few minutes and the Michaela changed the subject, much to my relief. That night Michaela made no bones about it and went into my bedroom as Lance and Carla watched and then went into Carla's room. Michaela was all over me and we made noisy love for what seemed like hours, before we went to sleep. Next morning I was up making a cup of tea when Carla walked in still totally naked and kissed me. She stroked my cock as we kissed. My cock grew and I turned her around and across the breakfast bar and slipped my cock into her from behind. We were fucking each other hard and had not noticed that Lance and Carla had come down and stood watching. I shot my bolt earlier than I really wanted due to having an audience. Michaela didn't mind the audience and I think it might have even excited her as she came with me. "Hey, not bad for an old man," he laughed, " hope I can pull and shag girls as well as you when I'm your age." We all laughed as Carla slapped his arm. The three of them played in the pool after breakfast, the only difference was that they were all totally naked. At lunch they sat at the table naked as if it were the most natural thing in the world. There was nothing sexual about it. Late in the afternoon Michaela come to me in my office and kissed me. "You need to loosen up bit she told me as she undressed me. She flicked my cock with her fingers and then went back to the pool with the others. I came down later and found them on sun loungers Lance and Carla on one and Michaela on another. I joined Michaela on hers and she cuddled up to me. A short time later Carla was stroking Lance's impressive cock. It wasn't long before he was between Carla's legs and taking aim at her fanny. Michaela was pulling me to do the same. Then we were all screwing. The girls groaning as Lance and I poked away at their fannies. Lance suggested a swap. I refused, screwing my stepdaughter was a step too far for me. Michaela and I finished first and I watched Lance's cock plowing Carla's wet fanny. My cock started to grow again. As Lance and Carla cuddled, "Look you dirty old man I ready for another go," Lance pointed out to every one. "Go on give it to her," he goaded. I took Michaela in doors and to my bedroom and gave her another sound fucking. Then when we returned I told them I would take them out for dinner and we all went to change. I rest of the three weeks the four of us were naked unless we were going out. We screwed whenever and wherever we liked. We had several more foursomes, without swapping, in the same room. That definitely got Michaela's motor running, she liked watching Carla and Lance as she was being banged. I was sad when my wife was coming home, although I was looking forward to seeing her, Lance had to go home and Michaela take all her stuff from my room. I managed to screw Michaela three more times before the girls returned to Boarding school. It was the best summer of my life. I'm now looking forward to Christmas as my wife just informed me that Michaela is coming for New Year. It was hard, but I had to suppress my excitement.