Since our last encounter, I hadn’t really talked with Erica much. A few texts here and there were sent between us, but nothing too interesting. All the while, my relationship with Christy was becoming more and more distant. We spent less time together and argued more. Sex between us was almost non-existent. I would catch Christy flirting with guys right in front of my face when we were out at the bars (she and I had just turned 21). Who knows, maybe Christy was cheating on me too. At this point, if she were, it really wouldn’t have hurt me too bad. I was pretty much over with our relationship, and I could tell she was too.However, I don’t think Erica was truly aware of the extent to which Christy and I were drifting apart when this weekend in November came about. It was probably reinforced by the fact that I went with Christy to visit Erica that weekend to see how she was adjusting to college life. Of course, a girl like Erica was adjusting just fine. She was living in the dorms, adamantly opposed to the sorority life. But, almost hypocritically, she loved going to frat parties. I imagine Erica was finally getting the fucking she really wanted from those frat boys. I’m sure she was getting used and loving every second of it. Because of this, I was pretty sure our sexual exploits were over and done with. That was cool with me. I still felt mildly guilty about the whole situation.On the drive to visit Erica, I had told Christy that I would be spending some of the night with my friends from high school out at the bars. I have a lot of old friends that live in this city and didn’t want to spend the whole night with Erica and a bunch of dudes at some disgusting frat house. Plus, I honestly didn’t want to spend any time with Christy. She didn’t want to spend time with me either, I guess, because she was more than happy to get rid of me when we rolled into town.I called my friends up. We smoked. We drank. We went out to the bars. It was about midnight when I got a text from Christy saying, “are you going to come see Erica or not? I thought that was the whole reason we came down here!” Great…. Christy was drunk and looking to pick a fight… typical. I texted back to say that I’d meet her soon and then I bid goodbye to my friends.I strolled up to a frat house about a quarter of a mile away from the bar I was at and was greeted at the door by a bunch of meatheads who wouldn’t let me in. They were saying something about not letting any guys in but frat members. Something about me fucking up the ratio of girls to guys. I called Christy and she didn’t answer. Then, I called Erica. She brought her sister up and got me inside. I laughed a little walking by the frat dudes who were wearing tank tops in November for some reason.This night in particular Erica had ramped up her slut uniform quite a bit. She had on tight jeans with these black knee high boots on. Her hair was extra curled that night and it fell nicely on her shoulders. But here’s the kicker… she was wearing one of those low-drape tops that girls wear when they want to show off their tits. You know what I mean right? One of those tops that cover their boobs but doesn’t stop at the cleavage. It looked a little like this, but was blue: http://images5.yandy.com/Products/ES-9771-D-L2011.jpgI tried not to stare at Erica’s chest, but she kept shoving it right in front of me. I could tell she wanted me to look, so I indulged her a time or two and let her catch me staring. Throughout the rest of the night she would dance sandwiched between a couple guys. She was soaking up the attention and it was crazy to me how much this girl had transformed in the past few months. Before she and I hooked up the first time, she did not display much sexuality in an outward way. Now she was living the life of a college slut. I laughed to myself and tried to blame it on anyone but me… but who knows, it was probably my fault.I really think that Erica had no intention of hooking up with me this night. I danced with Christy for a while but we got in an argument when I went outside to have a cigarette. She always got mad at me when I smoked, but tonight I could tell she was just using her displeasure with my vice to get in a fight. I was drunk and I really didn’t want to deal with the situation. I told her to call me in the morning when she wanted to go back to the town we lived in and that I would just crash at my friend’s place. I walked away and didn’t look back.Now I don’t know if this is exactly how it went down, but this is what Erica told me. Christy came inside with a face full of tears. Erica told her she would come find me and get me to come back. Christy obliged and stayed at the party with Erica’s friends. I was walking down the street, not yet having called my friends, when I heard the sound of someone running toward me. I looked back to see Erica’s tits bouncing as she was jogging. She must have had a lot of tape keeping that top on, because if there weren’t any there that shirt would not have been able to hold in her perfect tits.“Hold up,” she said as she caught up to me. She explained to me what Christy told her. I told her I didn’t really care and that I was over the situation for the night. Erica looked at me and smiled as I lit up another cigarette. She put her hand on my chest and said, “I bet I can convince you to stay…” Turns out that Erica’s dorm was a few blocks from where we were. She ushered me up to the girls’ floor, which was practically empty on this Friday night. Her roommate was at the party we just left, so we had the tiny place to ourselves.Erica shut the door behind her and locked it. She kept facing the door and I could tell she was taking off the tape holding that loosely draped shirt to her boobs. She tossed the crumpled up ball of tape on the ground and then turned around. She walked slowly over to me and pulled the shirt so that all of the cloth was between her tits. I kissed her and groped at her boobs. She moaned as I took off my shirt. Now this is where Erica excelled at turning me on. If you weren’t able to tell already, the fact that I was cheating was pretty hot to me. Erica knew this. She kissed down my stomach and got down on her knees in front of me.As Erica started to undo my belt she looked up at me and said, “If I treat you right will you promise to treat my big sister right for the rest of the night?” I agreed. But then again, I would have agreed to almost anything Erica said in that moment. Erica pulled my pants to the ground and, like she had before, started passionately kissing my cock while moaning. After kissing every inch of it, she displayed her deep throating skills to me for the last time.After she sucked my cock for a little she took her shirt and jeans off. Like the good little slut she is, she put back on her knee-high boots so she could fuck me while she wore them. Erica walked over to her window, placed her hands against it, leaned forward, looked out to the campus where people were walking around only a few stories before, and shook her ass at me. I walked over and dropped to my knees. She was expecting me to fuck her but I ate that pussy like it was the last pussy I would ever eat. She came once. Then she came again. Both times she yelled out. Both times I’m sure people outside noticed.I stood up after spending what seemed like hours on my knees behind her and shoved my cock in her pussy. I grabbed her hips and fucked her hard and deep. She moaned over and over until she suddenly pulled away from me and sat up on the windowsill. I stood in front of her and slid my cock into her again. I don’t know why, but this time I could tell I was not going to be able to last as long as I usually could. Erica could sense this and she said, “You better not cum yet. Not in my pussy. I want it in my mouth.”I fucked her slowly, trying to hold back my orgasm. Soon, it was too much to bear. I told Erica to get on her knees and she started sucking my cock feverishly while her hand tightly gripped the base of it, stroking as she sucked. “ERICA!” I yelled out as I came. Her tongue flicked on the underside of my cock as I filled up her mouth with cum. “You going to swallow for me?” I asked when she pulled my cock out of her mouth.“No, I’m a spitter,” she managed to say as she let the cum drool out of her mouth onto her tits, down her stomach, onto her pussy, and then finally making a puddle below her on the linoleum floor. This was quite possibly the hottest, sluttiest thing I have ever seen in my life. After she was done playing the slut, Erica cleaned herself off, licked my dick clean, and got dressed. We went back to the party and on the way there she told me I had to be nice to Christy for the rest of the night. I was, but that was probably the last time Christy and I ever went to bed not mad at each other again.I guess now is the time to give this whole story some closure, so I’ll briefly explain the rest of my relationship with Christy. A few weeks later we broke up. She never found out about Erica and I; also, the things I did with Erica had nothing to do with my decision to not be with her anymore. Her and I both decided together that we were over with. It was a mutual break-up of sorts. Christy and I message each other occasionally to see how the other person is, but these messages are few and far between. She now lives in that big city where Erica is just about to finish up school. As for Erica and I, we never hooked up again. We never even talked about our escapades together. Whenever I run into her back in our hometown she always gives me a wink, but nothing more.As for me, I moved down south to another state to go to graduate school. It doesn’t matter where. What does matter is my lust-driven appetite for interesting sexual encounters has not waned. I’ve had a few other run-ins with girls that are story worthy. Maybe I’ll fill all of you in on them in the future. For now, marinate on these stories. But if any of you start to judge me because I cheated on my girlfriend with her 18-year-old sister, just remember you read all three chapters to my story, making you just as interested in this type of perverted activity as I am. Thanks for reading everyone.