I'm 22 now, but when I first began to notice how my step father looked at me sexualy, I was 17. Bill has lived with us since I was 14, even back then I would listen to my mom and Bill fucking. It annoyed me at first but I soon began listen intently, especially when I heard my mom asking him to fuck her in the ass.
I couldn't help myself and I was soon masturbating to the sounds they made as they fucked. Around the age of 17 my mom had an accident at work. It pretty much stopped their love making overnight and after that I'd often hear Bill masturbating to porn when my mom was out. My own sexuality and my libido was increasing and I started dressing in scanty clothing. Firstly because it was comfortable, but after noticing Bill looking at me, increasingly I'd do it to tease him, knowing he'd get a boner.
One evening when mom went over to a friend of hers across the street, I slipped off my panties, put on the shortest skirt and top I had and walked downstairs. I found Bill sat watching boxing, something he loves watching. Sitting across from him so he could easilly see what I was doing, I began to slowly open and close my legs, flashing my pussy at him if he cared to look.
At first he took no notice as the boxing was taking up his attention. So stretching out I spread my legs further and wider. It got his attention and straight away I knew he'd seen my wet pussy. His whole focus changed from the boxing to trying to get to see my pussy, although he tried to make out he was still watching the fight.
Not needing to wear a bra, I lifted my arms up and revealed my left breast as if by accident, apologising to Bill for exposing myself I watched as he excused himself as he went up to the bathroom. Quietly I followed him and could hear him whacking one off as he sat on the toilet. When he got back downstairs I gave him one long last look at my pussy, only seconds before my mom entered the house.
I swear my mom didn't have a choice that night and once again I listened to them fucking. It was the start of their sexual relationship renewed and I hornily gave myself credit for helping them. It didn't stop me from teasing Bill even then and for the next few years until I moved out, I would flash him my pussy, ass and breasts. Each time he and my mom would end up fucking and I'd play with my clit listening to them.
Now when I visit, Bill has become more open with his looks. I know if I wanted to I could have his cock any way I wanted it, but for now I'm getting off knowing he wants my love holes and can't yet have them.