AI girl

By Andrew Diaz©

After our second sexual encounter, my sister and I decided we could go on being involved in this kind of intimate relationship. We thought exploring our sexual desires could help us prepare for our future life, like when we had a serious relationship, or we got married. We established some rules though, like having sex just a week. This usually meant we would start fucking on Friday evening, and we would stay in bed until Saturday afternoon. At that moment, both of us were in college and lived in a big house, just for us, as our parents were living abroad.

I wasn’t interested in seeing other girls as I had everything here at home. I knew this was just temporary. I would get a real girl someday, but I was determined to enjoy what I was doing with my sister.

*****

One day I was coming home from college after another day of classes. I came earlier that day because my professor didn’t show up for my English class. I opened the door and came in. I went upstairs, and while I was reaching the second floor, I could hear the sound of the shower running, and I guessed my sister was taking a shower. I thought about her big round tits, and I decided to pay her a visit, just that as I was getting closer, I heard some sounds.

First, her moaning, but then I heard some kind of loud bang, over and over again. Was she having sex with anyone else? I could not help but peek, and what I saw was just shocking. She was there in the bathtub on top of my cousin Ronald. His big cock was inside my sister’s sweet pussy.

I didn’t know what to do. I was angry. I was so mad that I decided to get into the bathroom.

“What the fuck are you guys doing?”

They looked at me and immediately stopped.

“Oh my god!” that was all she could say.

“Cousin… man…”

Even my cousin was speechless.

“I didn’t know you were coming so soon,” muttered my sister.

“Yeah… My English class was canceled,” I replied. I looked at her, and she could tell how mad I was.

“Andrew… I…”

“Slut!” I shouted at her. “And you…” I looked at my cousin. “Fuck off!”

I walked away and went to my room. I didn’t know what happened next between them because I was so furious that I decided to lock myself and play some loud music.

Twenty minutes later, she knocked on my door. I opened it, and there she was, wearing white panties and a red top. I could tell she was not wearing a bra since her erect nipples stood out.

“I’m sorry! Ronald came, we were having some coffee and talking, and then it just went out of control. I know I screwed up. Please… Forgive me,” my sister begged.

“You’re a fucking bitch. How come you ended up fucking him?”

“I told ya… It just went out of control. Please… Don’t be mad at me. Plus, remember… We are free to see any other person if we want to. That’s one of our rules.” she said.

“Just go away,” I said.

“Really?” she asked as she pulled up the right side of her top and flashed her right tit. She knew I could not resist the temptation to fuck her.

“You’re gonna pay for this if you really want me to forgive you.”

“I’ll do whatever it takes.”

“Are you sure?”

“Yes, I am,” she replied.

“Come here!”

I grabbed her waist and brought her closer to me. Her tits pressed my chest, and I got a glimpse at one of her juicy nipples. I rubbed it with my right index finger and immediately got a hard-on. She smiled and grabbed my cock tightly. It felt so good, but I had to remind myself she had just fucked my cousin.

“So, are you going to make me pay?” she asked softly with an evil smile in her face.

“Fuck yeah!”

I got behind her and grabbed her 34D natural boobs. I squeezed them and she moaned. I took off her top. I started to push her very slowly towards my bed, and once we were next to it, I took her arms and made her hands rest on my mattress while I bent her back.

I took off my clothes, and then I removed her panties. I kneeled down and my face got close to her ass. I grabbed her buttocks and made them bounce. It looked so sexy. I moved them sideways and directed my mouth towards her asshole. I started to lick it, trying to penetrate her hole with my tongue.

Her body shook, and I could hear a deep hiss. I licked it several times and then started to introduce my index finger, little by little. I could tell how aroused she was. I continued introducing my finger deeper and deeper, and at the same time, I tried to lick her hole. Then I stopped. I told her not to move and walked towards my night table.

I opened the drawer and grabbed a bottle of lube. I removed the lid, got some, and put it around my hard cock. I looked at her and could see her hanging tits waiting for me. I got closer to her, put some lube on my fingers, and rub it around her asshole.

“What are you doing?” she asked.

“This is my revenge, bitch. I’m going to fuck your ass! This is gonna be your first anal experience, one you’ll never forget, fucking slut.” I whispered.

When I started having sex with Valentina some months ago, she had made it clear that she didn’t want to have anal sex. It seems that she had tried with an ex-boyfriend, but it had hurt so much that she had decided not to do it again. She did let me finger her ass as she found it pleasurable, but that was it. However, things were going to change if she wanted me to forgive her.

“No… Please, it’s going to hurt,” she begged.

“It’s that or you will have to forget about me… I’ll be gentle, I promise.”

“Oh gosh… Ok… Gentle!” she requested.

“Sure… Don’t move!”

I put more lube on my right index finger and introduced it deep inside once again. This time, I went deeper, and again, I knew she was in ecstasy. I took my finger out, grabbed my dick, and started to rub her hole gently. I told her to bend more, and so she did. Then, I pushed my cock inside, slowly, very slowly. She moaned. I got to introduce my dick a little bit more, and more, until she groaned. I knew she was in pain.

“That’s what you get for being such a whore.”

“Do it slowly, pleaseeeee,” my sister pleaded.

I waited a little bit and then pushed again. Half of my big hard cock was inside her ass. It seemed that the toughest part had already happened. My dick went out a little bit, and then I pushed again. I repeated that movement three or four times and started to get deep into her asshole. Valentina groaned in pain again. I spread some more lube on her back and let it drip onto her ass and my shaft.

“Are you Ok?” I asked.

“I think so. Just move slowly, please”.

I thrust again slowly. I pushed a little bit more, and a little bit more. My cock began to go deeper and deeper until all my shaft was inside. I touched her tits and then I squeezed them. God if I enjoyed them. So big, so round, just like her ass. My hard dick moved inside her hole slowly, gently. I slammed her ass and pushed a little bit harder. She moaned. It felt so good to be inside that tight asshole.

Then, I started to rub her clit. I had totally forgotten about it, and when I did, she cried out loud. She was really enjoying it. I wanted to explode inside of her. I kissed and licked her back while she moved one of her hands towards my balls. She grabbed them and played with them gently. It felt so good.

I got a little tired, so I told her to lie down on my bed. She did. I lay on the bed too, spread her legs, and my mouth looked for her pussy. I licked it, and Valentina moaned. I did that for a minute or so, and then I focused again on my target. I reached her asshole and inserted my tongue. Her hole was bigger now. I played a little bit with it and then I kneeled. I grabbed her legs, pulled them towards my body, and put my cock inside her anus one more time. As I fucked her asshole, I inserted my thumb in her pussy. Her moaning increased, and I could tell Valentina was delighted.

I started to move faster and faster. she screamed, but this time it was one of pleasure. I grabbed her tits and rubbed her nipples again and again. She gasped, and I felt so good. I was about to come. I couldn’t resist anymore.

“So, did you like to be fucked in the shower? Did you enjoy his cock?” I whispered in her ear while I slammed her ass.

“No, I only enjoy yours. Gimme more… More…Please… Fuck me more.”

“Do you like how I fuck your ass?”

“Yeah!”

I thrust harder a couple of times more until I exploded. It felt so good I couldn’t believe it. I rested my face on her belly for a minute while I got some strength back. When I did, I put my left hand in her pussy and began rubbing it while my flaccid cock was still in her ass. I moved my hand along her pussy slowly, and after a while I increased the pace until her thighs started to shake, and so I knew she was about to come.

I sped up, and she screamed louder and louder. A huge climax invaded her body. I took my dick out of her anus and kissed all her body, exploring every single piece of skin.

I was so happy about my revenge, and it seemed Valentina was full of joy too. She would never forget her first anal experience. I was certain about it.

This story is part of a compilation of 25 erotica stories that are included in the book Sex Stories by Andrew Diaz. If you want to buy the book, you can purchase it in our store: https://payhip.com/b/h1RPb