Prologue: The Unspoken Attraction

Well I'm 21 and I have a little sister that is two years younger than me. She's always worn really skimpy clothes around the house. Her favorite thing to wear is really short shorts with a simple t-shirt. I've never found my sister sexually attractive when we were younger. But now she's growing and it's starting to show. She's 5'1 and maybe around 105 pounds. She has a petite body frame but her body is tight in all the right places. She has very shapely legs that seem to have just the right amount of meat on them. Her stomach is flat and she has a nice little tight round ass, she has little perky tits. She's as beautiful as they come. She's in college and she has a boyfriend now but before she settled down with her boyfriend word around was that she was a little slut at school.
It all started on the day that I had forgotten my wallet in my pants because I was in a hurry to get to work. I had gotten to work when I realized that I was hungry and wanted to order a pizza. I had remembered that I left my wallet with my card in my pants at home, so I gave my sister a call because I knew she'd be home. When she answered her phone she had her usual whatever tone in her voice. I told her what had happened and I asked her to get my wallet out of my pants and read me my card number. She said "okay hold on" a couple seconds passed and she began to speak with a confused tone. She said "ummm what did you want me to do?" As if she had lost track of what she was doing because of what she had found in my wallet. I thought nothing of it and asked her to read me my card numbers, so she did. When I arrived home that night my sister was already asleep. I went to brush my teeth before going to bed when I decided to get my wallet out of my pants. When I opened my wallet I realized what my sister had seen earlier. I had a couple condoms in my wallet for just in case use. I guess she must've felt awkward finding them.
The next morning I was sitting on the couch watching tv. My little sister had came out of her room and she seemed more energetic than usual. She saw that I was up watching tv already so she walked over and stood right in front of me blocking the tv. She was standing right in front of me. She began to lift up her shirt exposing her flat stomach. She pulled her shirt up just to right below her black bra. She looked at me and smiled and said "look I've been working out , what do you think? Do you like it?" I felt my cock rising. I didn't notice that I hadn't answered because she kept shifting her hips in a mesmerizing way. She resorted herself and all I could say was "yeah you look alright." I was confused because I was picking up a different vibe that I've never felt from my sister. For a second I could've sworn she was teasing me and enjoying it. I went to work the rest of the day. The next morning I was in the kitchen looking for something to eat when I heard my sisters footsteps coming into the kitchen. She was wearing a loose shirt that showed her little cleavage and she had on some booty shorts that she had outgrown because they barely covered her. She saw me and said "good morning, do you like my tease?" I gave her a confused look and said "what tease? She said "my hair tease" and pointed at her messy hair. I shrugged and went back to looking in the fridge. My sister then walked in front of me pushed me back so she could bend over and grab the orange juice out of the fridge. When she bent over I couldn't help but notice the bottom of her round ass was showing. I gazed over her legs and noticed how long her legs looked for her height. She must've bent over for maybe 10 seconds but it felt like an hour to me. She grabbed the juice and turned back at me and smiled before she went to her room again. I went to lay down on the couch. I couldn't stop thinking of how how my sister was. I couldn't stop thinking of how much I wanted to fuck her. I had my self worked up so my cock was at full attention. I heard my sisters door begin to open. I decided that I was going to pretend to be taking a nap. I put my arms over my face and pretended to be asleep. My cock was still at full attention. I heard my sisters footsteps get closer than suddenly her steps slowed down. I took it as a sign as she had seen my boner. I waited till she had gone back into her room.
The next morning I had come home from work and decided to lay on the floor in the living room I had heard noise coming from the kitchen but thought it was just my mom making something. But then I saw my sister come out wearing the same pair of shorts she was the day before. She didn't say anything just walked passed me, but as she was passing I noticed that her shorts were pulled up higher than usual. She had them up so high that her black panties were showing. Her panties weren't doing much help because I was able to see her tight little ass just showing out in the open. She looked back at me and smiled as she walked away. That's when I knew that my sister wanted to fuck. Now all I had to do was figure out a way to make it happen.