The trouble was, my sister was younger than I was.
So I knew Poll had her boyfriend in her room which was not allowed when our parents were home. So I guessed they were making out. I was in my room and decided to see if I could find out what was going on. Our rooms have a closet in them and each closet backs onto the other. There is a vent in the wall and I took a chance that Poll might have her closet door open. I pulled a chair to the wall and stood on it. Luckily, Poll's closet door was wide open and I could see her bed. What I saw ON it though, blew me away.
My kid sister was stark naked apart from her panties which were pulled to one side and her boyfreind was kneeling on the bed between her legs. I could clearly see her reach down and guide his erection to her pussy. At first, I thought they were just pretending. You know, kinda teasing each other. But then I saw Polly arch her back and he slipped right inside her. She didn't yelp or anything so I guess she had done it before. My kid sis, was definitely NOT a virgin! Then I saw them fuck. Of course, I had to go at it myself and I reached in my skirt and jammed my hand into my panties. OMG I was so wet you can't imagine it. I watched them as he suddenly reared up above her and said 'Fuck, Poll, I'm gonna blow'. Well, my sweet little kid sis said 'Cum in me. Do it inside me.' I watched as he cummed in her and even saw a little of his cum when he pulled out after Polly had cum.
I hadn't finished but holy shit was I horny. They both got dressed and then I heard Polly calling me! Shit I was so horny I just HAD to cum. Polly said did I need the shower and I said no. Then she went in and cleaned up.
I made small talk with her boyfriend but all I could think about was his cock inside her. I would have fucked him over the table there and then. I ached to have him in me too. When Polly came out of the bathroom I went in and locked the door. Nothing was gonna stop me cumming now! I stripped naked and spread my legs. I love masturbating standing up and just as I touched myself I saw Polly's panties lying on the floor. I picked them up and of course, they were full of his sperm. I had them to my face in an instant and athough I could mostly smell him, I could also smell Polly's cunt on them too. This was really kinky for me and as I licked Mike's cum off her panties, I knew I was also licking my sister. My orgasm was so massive that I actually wet myself. As I felt myslef cum and pee I pushed Polly's knickers inside myself. I know this was really stupid because I could have got pregnant, but it was so fucking horny.
Later, a few weeks later, I told Polly that I had seen them and that I was jealous as all hell. Polly said that she didn't mind if he took my cherry too. Unfortunately for him that didn't happen. (Actually, I lost my cherry when I was 15 to a middle aged man and it was totally stunning.)
One thing that did happen is that Polly and I masturbate together sometimes. Sometimes we touch ourselves only, but sometimes we touch each other too. I know it's my sister and all, but it makes it feel hornier if you know what I mean.