My family is a little strange, more than most. This story starts shortly after my 18th birthday. But first, a little background information.
My name is Ben. I am one half of fraternal twins. I'm older than my sister, Alexa, by three minutes and 43 seconds. Oh, my sister. She's an important part of this story so I'd better describe her. At 18, she was gorgeous. Barely 5', she weighed about 115 lbs and it seemed like ten of those pounds were in her bra. She wore a C-cup, but it looked a lot larger on her small frame. She had angelic features framed by shoulder-length dark brown hair. Expressive, wide-set brown eyes gave her an eternally surprised expression which was cute under normal circumstances, and incredibly sexy when she was on her knees with...but we'll get to that eventually. As for me, I was 5'9" and 150 lbs. Not overly muscular, but not a wimp, either. I had no problem lifting my sister's weight. Short brown hair and blue eyes completed my look. My cock was about six and a half inches long when fully erect. Not too shabby, but nothing to brag about either. All in all, I was pretty average.
We grew up very close, as most twins do. We talked to each other about everything, from sports to music to our troubles and triumphs with the opposite sex. As it happened, we both lost our cherries on the same day at the same party. We didn't know about it until we got home and told each other about it. Strangely, I felt kind of jealous of the guy who had been with Alexa. Throughout high school we both went on dates and got laid, but whenever a guy came to pick her up, I didn't like it.
By the time we had turned 18 I had started fantasizing about her while I masturbated. Our birthday was towards the end of May, so school was almost done. Our birthday party was quite a blast. Our parents were pretty cool about alcohol, as long as we didn't drive, we could drink. All night long I was flirting with one of Alexa's friends, a girl named Maggie. Maggie was a cute redhead, petite like Alexa, but with smaller tits. By one a.m., she was fairly drunk and rubbing those tits on my arm. I wasn't entirely sober myself, and though I was growing hard, I just wasn't into it. Earlier I had seen Alexa talking with her boyfriend, a football player named Steve. I didn't see them anywhere, so I figured they must be fucking up in her room. That thought kind of depressed me, so I politely extricated myself from Maggie and went to bed.
__________
The next day was Saturday, so I slept in. When I finally came out of my room, I saw that Alexa's door was still closed. I thought that was strange, since Steve never stayed the night and no matter how late she stayed up, Alexa was always awake before me. I knocked on her door. "Alexa?" I asked. "Are you in there?" I heard some faint sniffles through the door, so I decided to take a chance and opened it. Alexa was laying on her side with her back to the door, sniffling.
I walked over and sat down beside her and put my hand on her shoulder. "Lexi?" I asked, reverting to my childhood nickname for her. "Are you ok?" At my question, she turned around, buried her head in my chest and started sobbing. All I could do was stroke her hair and whisper consoling words to her. Eventually she stopped crying and sat up.
"I'm sorry," she said. "I didn't mean to do that to you."
"That's ok," I replied. "Can you tell me what's wrong?"
"Steve. He broke up with me last night! He said something about wanting to be free for college."
"That bastard!", I exclaimed, wanting to hurt him for hurting my sister.
Alexa nodded, "And to top it off, after he finished breaking up with me, he asked if I wanted to go fuck. He said that we could still have fun. Can you believe the nerve of him?"
I was shocked, but I had to laugh too. At her indignant look, I said, "I guess you're just too good to completely give up."
"Of course I am," she replied with a ghost of a smile. "Now get out of here so I can get dressed."
I spent the rest of the day doing errands for my mom to help her get ready for graduation on Sunday. My sister was helping around the house, so we didn't see much of each other. That night, mom and dad went on a date, so I went downstairs and popped a movie in. Eventually Alexa came down to join me. When I caught sight of her, I nearly gasped. She was wearing a spaghetti strap top that was just loose enough to let her bra-free tits wiggle, but not so loose that it hid her figure. Her top ended an inch above her bellybutton, showing off her flat stomach. Her shorts were so short that they barely covered her ass.
"Are you going to make room?" she asked me, gesturing to the couch.
"Sure," I said, scooting over so my back was to one of the armrests and my right leg was extended along the back of the couch. I expected her to mirror me, but instead she leaned against me, with her back against my chest and the top of her head under my chin. My arms reflexively curled around her, with my right hand resting on her stomach and my left on her upper chest. It was a position we'd used to sit in, but we hadn't for several years. We sat like that and watched the movie. I tried not to think about my sister's tits and how close my hands were to them, but it was a losing battle.
Eventually, a sex scene came on. I was having a hard time controlling my erection with my hot sister leaning against me, so with the added visual stimulus I got hard.
My sister must have felt it pressing against her back, because she squirmed against it and asked, "You like her?" referring to the topless woman on the screen.
"She's alright, but I'm into someone who's hotter," I replied.
