Coming back to the flat after Christmas was a bit of an anti-climax. It's like the second week of a holiday; it's still enjoyable sleeping in a different bed but knowing you will return to normal soon. When we returned, I missed sleeping with Sophie every night as we did just before I left. That didn't mean we stopped having sex; we just had it shortened and faster. Some mornings, as Dad left, she would drop into my bed, have a quickie, return and be slightly late for work.

Or I would wait at the front door at 5:55 and take her in her office clothes against the front door. This added to the cleaning bills and ruined several pairs of stockings, so she was less pleased, although I only ever did this after a text from her in the lady's toilet at her work at 4 pm. On Thursday nights, Dad worked late or had a business dinner with clients. Sometimes he could watch us fucking at his desk but constantly texting when it was time to stop.

On Friday nights, Colin stayed over and left after a late breakfast. Dad would drive him to the station and go to his office for several hours. Sophie and I would fuck all over the flat, and Dad could watch it from his office on the CCTV. I'm being a bit selfish, though; the time for sex itself is enough, and I'm certainly not getting blue balls. Additionally, in the three months of winter, he went away for around a dozen nights, but never more than two together, never on a weekend.

What seemed to stop almost immediately was the family time before, when they were gently building me up to sleep with my Stepmom. The cuddling on the sofa when we watched TV, the crazy phone conversations when Dad was away. The blatantly exhibitionist clothes Sophie wore around the flat drive me horny; I miss out on. Dad was very territorial, and I was not going to cause a fight because I was happy with the status quo.

What it seemed to gravitate towards was that when my father was out of the flat and his wife was in the flat, we fucked like rabbits. Not spending any time other than providing orgasms for the lady of the house. Plenty for me as well. When Dad was there, the interaction with me was minimal. We did have dinners together, which was great, but I left for rowing training or something else at college almost straight after dinner. If Dad and Sophie were at home, they watched TV in bed.  

Sophie and I had plenty of time for long conversations while waiting for Dad to go away for a more extended trip. Sophie told me more of her story. After college, she moved to the city with her nest egg to have all the sex she could. It was a year or so into her stay when she accidentally had sex with a guy with a big dick. He was the roommate of someone she was fucking and had a threesome. This was a lightbulb moment because the extra depth touched sensitive parts inside her.

This gave her the satisfaction from sex that she needed. Unfortunately, she went on a hunt for big dicks, and some of the guys she hooked up with made her do things that she didn't want to do really but did for the result. They humiliated her, made her fuck their friends first and then didn't even fuck her in the end. She hated it but loved it, too. It was then she met my father, who gave her sexual satisfaction without making her do those things she didn't want to do.

He opened her eyes to things she did want to do, like swapping and parties. She said that Dad gave her the space, even when married, to do everything she needed to get all the sex she wanted in a stable framework. The only thing she was sad about giving up was a gangbang. She was out of control at the group's whim when she did one, and she loved that. She told me that she last had one at Dad's stag night.

His mates had never met Sophie and were not coming to the wedding as I knew, so she came as the stripper to the flat and had sex with everyone, Dad being smug about it. The guys used her because they thought she was being paid for it, and she loved every minute. Unfortunately, it spooked Dad a bit, and he hasn't allowed her to do it again. She fucks lots of guys at parties, but it's all under control which is the bit she wants to get past. I put that one away for the future. 

What came out of these chats was that Dad was happy for Sophie to screw other guys; he was just worried that she might then prefer to live with him. As a result, she went with him to swapping parties and also went to Georgios. I didn't understand this comment, but she said we could go together. Perhaps when Dad was away next time, I would appreciate it. So fucking, Colin would be okay with Dad, I offered, and she said that would be fine.

I was a bit gobsmacked because Dad always told me Colin could not stay over when he wasn't here. Then, I found a lot of my father's attitude odd. On the other hand, Sophie wouldn't do it because it might complicate my life. I was somewhat surprised because I had never thought I might be affected. Colin boasted a lot, so if he claimed to have fucked my Stepmom, nobody at college would believe him. If I lost his friendship, it would not be a killer.

Other guys could fit the bill, even if Colin were the one I would prefer to keep. The upshot of this was that it was up to me; Sophie would be happy to fuck him, with or without me, preferably with. Dad would probably be okay with it because he knew Colin, like me, was no threat to Sophie leaving him. I had a word with Dad about it. Did he mind Colin shagging his wife (not those words, of course)? He said Sophie could do what she wanted within the parameters agreed upon.

Dad did not tell me the parameters; of course, Sophie would understand what they were. I didn't need to remind him that I still held the CCTV over his head; in the same way, he was being a dick, I was one too. He said he thought that Sophie was going for a few drinks after work next Friday, which was all a bit cryptical. He mentioned that Sophie had enjoyed the sheet and ping pong game with my friends. It was a good thing that Colin's cock was a decent size.

I was lost in the conversation until he mentioned that he might have an emergency at work. I thought I understood it now. So that's what happened the next time Colin came over, and Dad rang up mid-afternoon. He had to go away to fix a problem with a client, which might involve a stayover. Get a takeaway. This was all on speaker, so Colin heard it all. Colin jumped up in the air for a while until I told him Sophie was out for drinks after work, and he got annoyed again.

Anyway, we played Xbox for a while, then watched some porn on the big tv at my suggestion. Sophie finally came home around eight and behaved as if she was drunk. We met by the breakfast bar, porn in the background; Sophie had already sorted out her clothes in the hall, and her bra was off. She was already wearing her shortest work skirt and her most transparent blouse, but she undid a few more buttons, making her look slightly sluttier than usual.

Dropping her jacket on the chair, she demanded more wine and sent me off to the kitchen to get it, meaning she could greet Colin, give him a big hug, and then half sit down and half fall onto the sofa with him. She ended up as she wanted to, his arm around her, her hand on his thigh, her skirt flashing her stocking tops, one leg up on the sofa forcing her legs apart. She then started to talk about the porno film: which one was this? Colin, what did I miss?

Is this a naughty stepmom film? What happens next? I think Colin was a little overawed; for all his flirting and attempts to seduce in the past, he was stunned that it was finally happening and didn't know what to do. I arrived with the wine and put it on the coffee table, telling Sophie that Dad had an emergency and might not be home tonight. I allowed Sophie to tell Colin that she had all night to play with her favourite boys.

I sat on her right side, but she turned to Colin, asking him again about the porno film, and this time, he started to talk and inform her yes it was a stepmom film and the son and his friend were spit-roasting her. 'Ooh,' Sophie went. 'I love a spit roast; what end do you prefer, Colin? Do you want to be sucked off or do the fucking’? I think Colin finally woke up and moved in to kiss Sophie. They started kissing, and I just watched them and let Colin do his stuff.

He probably thought he would be taking Sophie to bed, not both of us, and I wanted him to get used to the idea before we let him down. I sipped the wine I had poured for Sophie whilst Colin got enough courage together to feel Sophie's breasts and put a finger into her thong. It was roughly at that point that Sophie pulled herself off him, pushed him back and fished out his cock before slipping it in her mouth. I knew he was in for a treat.

After the ping pong, we both knew he was a reasonable size, but Sophie could take him all. An odd thing happened at that point, which didn't surprise me. Colin started to talk as if he was offering a commentary on a porn film taking place in front of him and talking to Sophie as if she was a cheap hooker. I think I've mentioned before that Colin watched way too much porn and seemed to believe that real life was like a porno. And you could talk like that to girls.

I was half expecting her to spit him out and slap him, but she seemed to get a real kick from it. I remembered the chat about the big-dick guy and hating/loving the humiliation and losing control in a gangbang and understood. Colin started to give Sophie a critique and instructions; 'Can't you get more in your mouth, slut. Cup my balls, take off your blouse. Let's see you do a little lap dance. Oh, she is doing something interesting on the TV, let's do that.

Sophie followed it all to the letter until I started to get a little bored, so I pulled up her skirt and slipped some fingers in her pussy. She was soaking wet, more so than usual, and after casually playing with her clit pulled down her dress and thong, leaving her stockings on and moved her into the doggy position. This had no resistance at all, and sliding in halfway didn't stop her from lavishing all her attention on Colin's cock.

I enjoyed this immensely; don't get me wrong fucking Sophie was the best fun I'd had in my life so far. But since that first weekend, she has always commented, 'It would be better if you did x or y'. 'It was all great and made me a better lover for sure, but sometimes I wished she would enjoy what I was doing to her right now. I wiggled around, played with her clit, and slid a finger in her asshole whilst slowly, gently working my way entirely inside her.

The feeling was tight, wet and wonderful. I knew I would need to go slowly so I didn't distract Sophie from having the fun with Colin she wanted to. After all, I could pretty well fuck her anytime; Colin might just get the once. I must have been doing the right thing because it wasn't until I was entirely inside that Colin noticed I was joining in. 'Hey man', he called out, 'you get a piece of this slut too. You have been fucking her for a while as well. I can't blame you.'

'She is an excellent piece of ass.' This mortified me because if I had said it, Sophie would have chewed me out, but Colin seemed to get away with anything. He started to absently caress her nipples, pinching them in turn, causing a shudder to pass through Sophie's body, but she kept her mouth full the whole time, and no words apart from a slurping noise passed her lips. This was turning out to be a Friday night of legends.

Colin seemed to wake up, and he returned to his porn dialogue. Telling me what slutty MILF my Stepmom was and how she needed to take him a bit deeper in her mouth. He then described to me how Sophie was taking his cock right down in her throat and that her nose was on his stomach. Not that I hadn't had fifty of those same blow jobs, and my cock was at least three inches longer than his. On-screen, the female lead was now being spit-roasted by the two boys, so Colin instructed Sophie.

He didn't say it politely; it was more like. "Hey slut, get up on all fours so I can fuck your face, and you can get that sopping cunt of yours filled with your stepson's horny cock. I'm' going to fuck your face until I come all over your tits; get to it." I thought this was going to piss Sophie off; I mean, I knew she was finding getting fucked by us both a big turn-on. Her pussy was a lot wetter than it was with just me, and the way she just smiled and went with everything.

The way Colin told her what to do with enthusiasm made me realise she was just getting turned on by the whole thing. I then remembered her telling me about how the guy in her past with the big cock made her do everything he wanted, and she said she lost control and just did it. It seemed Colin was pulling the same triggers in her. On-screen, the spit roast had ended, and both boys were double-teaming her pussy and ass.

I figured Colin would notice soon, and we would do so too. So I started to open up Sophie's' ass to what I knew would be a straightforward entry. It struck me at that moment that I had never shared a woman before, had a threesome and more with multiple women before Xmas, but this was a first. Since Colin had shared his sexual experiences with me, exaggerating them as I downplayed mine, I knew he had never done anything like this.

It wasn't long before Colin switched the 'slutty MILF' over. This is what he was calling my Stepmom. I could see what was happening on screen, so I laid on my back; the slut was told to sit on that big cock and was pushed forwards so Colin could get into Sophie's' ass. I had worked it wide enough to fit mine, so it was pretty easy with the lube in my top drawer. When Sophie's phone rang, Colin was in balls deep, starting a decent pace. We let it ring out; Sophie and I knew it was Dad.

I was also pretty sure he was watching this live in his office, not hours away at a client's, although I was not 100% sure without checking. Sophie asked Colin to slip out and get her phone, then handing it to her, he slipped back in her ass and started a steady pace that Sophie was struggling not to cry out at. She rang Dad back after telling us to try to be quiet. A surreal conversation occurred with the phone on speaker on the sofa by my head.

Sophie quickly explained that she had recently arrived home and was making Colin welcome. We were watching some porn, and the soundtrack was the sounds you could hear. Was this just the excuse for Colin to thrust into her quite hard? We had a surreal round of conversation on the phone. 'Hello Dad', from me. 'Hello Paul, yes, Sophie is making me very welcome' from Colin. Then, Dad explained he could leave soon and would be home in around 2 hours.

He would ring when ten minutes away so we could reheat some pizza, as he was starving. The call was cut short then, just as well. Sophie came with a big squeal a couple of minutes later; it was the first of a lot of orgasms, as we now knew we were on the clock. Colin fucked Sophie's' ass like a man possessed and, when he was close, pulled out to shoot over her back in a classic money shot. He called out to the slut to 'like clean up his cock'.

To my amazement, Sophie hopped off me and sucked it clean, then Colin back to hardness. All in all, he fucked her ass three times and her pussy once. As the two hours were nearly up, Colin came all over 'those slutty MILF tits', as he called them. We all got up and went to our respective bedrooms to clean up. Shortly afterwards, Dad rang to say he would be there in about 10 minutes. This was about the time it took to get from his office in...