My Sister Shelly

I'm Bruce 26 single mechanic and live with my parents and 2 siblings. Our parents and younger brother went away for a week and I was home alone with Shelly 23 works as a shop assistant. They left on Friday morning and were returning the following Friday evening. I got home from work and had got my dinner on the way home. Shelly was going out and I was home alone and had no plans to go out myself. Shelly got home just after 10 pm and was left at the door by her date Scott and she was looking for her keys. They had argued and that had cut their date short. Shelly was a little drunk and after I had let her in, she started drinking again. I left her drinking and went back to watching the movie I had been watching before she returned home. After the movie was finished, I turned off the TV and went to make a snack. I found Shelly sitting totally drunk and talking to an empty chair. She was talking to the chair as if Scott was sitting there and continued on to make my snack. I could hear her, she said that she was horny and wanted to have sex with him. By the time I had finished my snack, she had her head down on the table almost passed out. I turned off the lights and told her to go to bed and sleep it off, she replied she wanted me to fuck her and make up for the earlier fight. I realized she thought I was Scott and told her I was Bruce. But it didn't register with her or she couldn't hear or something being so drunk. I had to carry her to her bed and I laid her on the bed and she sat up and started to undress talking to me as if I was Scott. Shell has a great body and a pretty face and I got horny with her wanting sex and talking to me about fucking her. All be it thinking I was Scott and I decided to play along and see how far she would go. Expecting her to pass out or just go to sleep, I dropped my pants in front of her and grabbed my hard cock and was soon sucking it. I blew my load into her mouth without telling her her I was about to cum. She swallowed it all and wanted me to fuck her so I did and after I had blown my load inside her, I laid beside her and she went to sleep. I thought for a while and then got up and cleaned her up and I found her dildo in her pantie drawer, I rubbed it along her pussy and left it beside her and went to my bed. The next morning I was up and started to worry that she realizes it was me and get upset. But she didn't wake until noon and asked me when Scott had left and I said Scott hadn't been here at all. She seemed confused and went back to her room. Around 2 pm she returned saying she must dream it. That was 6 weeks ago and she hasn't said anything more about it since.