Drunk Sister

I came home from working the late and found my sister Megan 20 trying to open the front door but kept missing the keyhole with her as she was drunk. She had been to a party and they had dropped her off and left her outside without making sure she got inside first. Being underage and drunk could've got her into trouble she was found a police patrol. I opened the door got her inside our parents were away visiting our older sister and her new baby. I took Megan to her room and left her and went showered and get ready for bed myself. I just got out of the shower and was drying myself. When Megan walked naked and straight out asked to fuck her as she said she was very horny. I wasn't sure I should but my cock went hard and so I took her to my bed and fucked her, in the morning I awoke first and got another hard-on. I was thinking of fucking her again when she awoke and told me to fuck her again. I'm Alan 23 middle child and since that night fucking Megan I've became her go to guy to fuck her. Her boyfriend had dumped her the night the party and took up with another girl. Megan was unhappy and drank too much at the party as a result, but getting fucked me made her happy she told afterwards. She hasn't dated since that party, except if you call going out with your brother dating. She is attending the local university and I work for the local power company. I still live at home and on my nights off I take Megan and regularly fuck in my car. I don't have a girlfriend unless you count Megan. Mainly due to working shifts which puts them off me, as I'm working usually went something comes up. Which they want to see and or a party they want to attend and I'm required to work. Megan doesn't care that I work shifts and use my time off to her advantage.