It was the morning after Julie and I had fucked for the very first time. I awoke feeling happier and more relaxed than I had in years. The memories of feeling my sister's mouth and pussy wrapped around my cock were so fresh in my mind that I could practically still feel her.
After a moment I realized it wasn't just my memory, I really could feel someone's lips wrapped around my sixteen-inch erection. I looked beside me to find Julie was missing, but there was lump under the blanket the looked just the right size to be her. I pulled the covers away from my body to reveal Julie with her mouth full of my cock. She was naked, just as she had been the night before, and she managed to smile happily even with her mouth so full.
"Morning, Jack," she said, pulling herself off of me for a moment. "I'm sorry, I just couldn't wait for you to wake up."
"I don't mind," I said. "This seems like the perfect way to start my day; being woken up by a blowjob from the sexiest girl I know."
Julie smiled even wider and went back to sucking me off. Within a matter of seconds she managed to take my entire length inside her mouth and throat, her forehead pressed against my stomach. She had gotten so much better at her blowjobs just since yesterday when I'd had to help her take my whole cock. She was a pro at it now.
I groaned as I felt my sister's throat contract and pulse around my shaft. It was already so tight in there that I couldn't believe I even fit, but when her muscles squeezed it somehow got even tighter. My cock was in heaven.
Julie bobbed her head up and down while always keeping my cock at least partly in her throat. She'd always loved the water and swimming, even becoming captain of the school swim team, and I assumed that must have had something to do with how good she was at holding her breath. Even the girls in the porn videos I'd seen weren't able to deep throat for as long as my sister was. I was so lucky to be her brother.
She kept working me for another ten minutes until I felt my orgasm starting. Her sexy naked body and her tight, skilled throat made it impossible for me to hold out any longer.
"I'm gonna cum!" I said.
Julie buried my shaft as deep in her throat as she could and let my cum erupt directly into her stomach. Since I hadn't cum yet that day, there was plenty of it. My orgasm went on for about five minutes and my sister dedicatedly took the whole load.
"Mmm," she said when she was finally able to sit up. "I love having all your cum in my belly. Now I don't have to worry about breakfast." She patted her tummy for emphasis.
"That was awesome," I said. "Your blowjobs are so good."
"Thanks. Now how about you return the favour and help me get off too."
I looked down to her sexy, smooth pussy. Her juices were running down her thighs, indicating just how turned on she was. We just had that kind of effect on each other. When we were naked together my cock was always hard, and her pussy never stopped lubricating itself. We were a perfect match.
"Come here," I said.
I lay back and let my cock point straight up in the air. Julie quickly moved to straddle me and position the tip of my erection directly against the entrance to her pussy. She started lowering herself, moaning loudly even before I was inside her.
Her pussy was even tighter than her throat. It was so tight that I worried ever single time that I wasn't going to fit, yet somehow I always did. Once the head of my cock slid inside it got easier, and the copious fluids she produced helped a lot too. Without all that natural lubrication penetration wouldn't have been possible.
Julie moaned even louder as she took more and more of my shaft inside her. Even though her pussy had to stretch so much to accommodate me, she insisted it never hurt and only felt good. She bounced up and down a little to help force me deeper. The first time we'd had sex she hadn't been able to take my entire sixteen-inch length without my help, but she'd gotten better since then.
Soon I was buried within her and she was sitting directly on my lap. She looked so proud of herself for her accomplishment, and also incredibly turned on. After pausing for a moment to savour the feeling of being filled up so completely she began bouncing up and down even harder than before, fucking herself on my cock.
"Oh god, Jack. Your cock makes me feel sooo good. I still can't believe my own brother's cock can make me feel this way."
"I know what you mean, Julie. Your pussy is so tight and amazing. Even though you're my sister, I love having sex with you and I love you so much."
Julie bent down to kiss me while continuing to ride my cock. We mashed our lips together and did out best to stick our tongues down each other's throat. She was going wild with her hips. She pulled almost all the off of me, then slammed herself back down over and over. After seven minutes and twenty-two seconds of fucking like that, we came at exactly the same instant.
"Oh fuuuck," we said together.
Even though I'd already cum once that morning, this orgasm was even bigger somehow. It was probably because Julie's pussy just felt that much better than her mouth. My cum shot out so hard and fast that it threatened to knock her off of me, but she clamped her body to mine and held on through the whole thing.
Her pussy was even tighter when she was cumming. Her muscles all contracted with pleasure, crushing my cock in a soft, loving embrace. Despite the perfect seal, somehow there was still room for her body to accept my cum. Wave after wave of my semen flooded into her and most of it stayed there. Only a little bit leaked out.
Suddenly the door burst open. Mom stood there with her mouth open in pure shock. Julie and I were caught naked with my cock still in her and no way to hide what we had just been doing. We both froze, unable to think of anything to say to our own mother who had just caught her children having sex.
"What are you two doing?!" Mom demanded.
"We were... I just..." I stammered.
"Mom, please don't be mad," Julie said.
"Don't be mad?! What am I supposed to think when I see something like this?!"
Mom turned around and left. Julie and I were left shaken and worried about what she might do. We had never meant to upset her.
"Jack, what are we going to do?" Julie asked.
"I don't know," I answered. "I never thought this would happen."
Julie chewed on her lips for a few minutes and looked thoughtful. Eventually she brightened up a little.
"There's only one thing to do," she declared. "We have to get Mom to have sex with you."
"Julie, that doesn't even make sense. If she was mad about us having sex, why would she ever want to join in?"
"Because," she said as she climbed off of my cock, "she hasn't seen this yet." She pointed to my sixteen-inch shaft which had yet to soften even slightly. "Remember, I never would have thought about having sex with you either until yesterday."
"That's true," I said, carefully considering her words. "If I hadn't accidentally seen your naked body, and you hadn't seen my cock, none of this might have happened. Do you really think it'll work?"
"I'm sure it will. I don't think there's any girl out there who could resist your cock." She paused for a second and frowned. "But listen, Jack. Are you going to be okay with having sex with Mom? Because that would be something you'd have to do as part of the plan."
I had to think about that one. Having sex with my own mother wasn't something I should even be contemplating, but then neither was sex with my sister and that had turned out better than I could possibly have imagined. I had to admit, Mom was actually pretty hot. That made the decision a little bit easier.
Mom was a lot older than Julie and me. She was nearly twenty-seven. She looked a lot younger than that though, even younger than Julie. The two of them actually looked very similar, and it was easy to see where my incredibly hot sister got her looks from. Sometimes when Mom and I were out together people would mistake her for my daughter. We always laughed when that happened.
One of the main differences between Mom and Julie was that Mom had much bigger breasts. Julie had a very lithe, athletic build that made her the sexiest girl in school, but Mom was a lot curvier. Mom's breasts were probably about a 56FFF size, but unlike most women with boobs that big, hers didn't sag even a little. At times it seemed like they must have been filled with helium because of how firm and perky they were despite their size.
I had to admit, given Mom's breasts and her looks in general, I didn't mind the thought of having sex with her as much as I should have. Having already broken the incest barrier with my sister probably helped.
"I think I'm okay with the idea," I said. "But what about you? Are you okay with me having sex with someone else?"
"It's only Mom," Julie said. "It's not like you'd be running around fucking random girls. Besides, now that we're having sex it's gonna be my job to make sure you have sex with other girls sometimes. I have a friend who's been fucking her brother for a while, and she told me that's the best way to make sure their relationship works. They have sex all the time and sometimes she brings in other girls and they're both so happy and in love. That's what I want for us too."
"Well as long as you're okay with it," I said. "We can discuss the other details later. Right now I think we need to take care of the more important business."
"Right. Let's get dressed and go find Mom. Hopefully she hasn't left the house. It'll make things trickier if she has."
Julie bounced off to her room and we both got dressed as quickly as we could. A couple minutes later we met up again and proceeded downstairs together. Fortunately Mom hadn't taken off and was pacing back and forth anxiously in the living room. She stopped when she saw Julie and me approaching.
"How long has that being going on?" Mom asked.
"That's not important," Julie said. "What is important is that Jack and I want to convince you that what we're doing is okay."
"I'm sure you think it is," Mom said. "But you're forgetting that you two are brother and sister. You can't have sex with each other no matter what you think or feel."
"But Mom-" I started, trying to help Julie convince her.
"No!" Mom said. "No buts. This is final."
"Fine," Julie said. "I hoped we could talk this out, but it looks like we're going to have to do something a little more drastic after all."
Julie instantly stripped out of her clothes, then tore mine off as well before Mom or I could act. My cock sprang to attention thanks to my sister's naked body, revealing its full sixteen inches to our surprised mother. Her eyes became glued to the sight of my massive erection.
"Jack... Julie... what..." Mom said.
