Roger and his family moved into the house next door when we were both ten years old and we've been best friends ever since. I've always thought that we were like mirror images: we sort of look the same, although I have dark hair and he's blonde; we both have one sister, they're each a year younger than us; we have normal, boring parents who are practically interchangeable; even our houses look alike, a pair of large, squarish, two-story homes in the middle of a crowded street. But if we are mirror images, Roger is the real one; I'm the reflection. He leads, I follow.
He seems to speed through life without effort; I can only plod along behind him at my own pace. While this is true about everything we do, it's especially true when it comes to women - he is more experienced than I'll ever be. We're nineteen years old but Roger is like a wise and dirty old man. He's always telling me stories and giving me advice. Sometimes he even lets me watch.
There's a large window in my bedroom, which is on the top floor of my house; by coincidence it is exactly opposite to the window in Roger's bedroom next door. When we were kids we discovered that, due to the shape of our houses and the distance between them, nobody else could see into our windows, either from the ground or from any other window. It was a secret connection between us, and it was pretty cool when we were kids; when we grew up, it was Roger's idea to leave his curtains open and his lights on when he had a girl in his room. It didn't happen that often, since it was usually hard for him to sneak a girl into his house, but when Roger would tell me that the possibilities were good, that night I would be in my room, lights out, sitting by my window, watching.
A few weeks ago, as I was getting ready for bed, I realized that this hadn't happened in a long time. I thought that maybe we had forgotten about our arrangement; Roger hadn't mentioned it lately, and I hadn't asked. I couldn't even remember the last time I had looked out my window, I almost always keep my shades down. So that night, just for the hell of it, I pulled up my shades.
Roger's curtains were open and his lights were on. He was with a girl. They were both naked. He was sitting on his bed and the girl was sucking his dick.
So Roger hadn't forgotten about our windows. But why didn't he say anything to me? His curtains would be closed if he didn't want me to watch. Did he want me to discover this on my own? I wondered what he was up to.
The girl took Roger's dick out of her mouth and stood up. That's when I saw her face - it was Becky, Roger's sister.
Holy shit. He was having sex with his sister. And he wanted me to see it?
I've always considered Becky to be pretty hot; I also considered her to be off limits, being Roger's sister. How's that for irony? She has long blonde hair, a thin waist, and rather big breasts. She's good friends with my sister Rachel. I wondered if Rachel knew anything about this. I wondered how long it had been going on. I wondered why, dammit, why was he having sex with his sister? It was completely unexpected.
Becky climbed onto the bed, on her elbows and knees, her ass in the air. She was looking at the window, her face resting against the mattress, almost looking straight at me, but my room was dark, she couldn't see me. Roger stood up behind her and slowly eased his dick into her pussy. Becky closed her eyes and arched her back, her tits brushing against the sheets.
"What are you doing?"
I jumped. It was Rachel, standing in my doorway. I had forgotten to close my door.
"Uhh," I said, like an idiot. My sister must have passed my room on her way from the bathroom; she was wearing a long shirt, ready for bed.
"What are you watching?" she asked, walking into my room.
I should have pulled down the shades then. I could have easily pulled them down before my sister saw anything. I didn't. I'm not sure why.
Rachel stood next to me by the window. "Oh, it's Roger," she said, not impressed. "He's such a horndog." She laughed and poked me in the shoulder. "He opens his curtains so you can watch? That is so sick!" Then she looked closer. "Wait - that's Becky! He's fucking his sister!"
"Sshhh," I said, but there was no way our parents could hear us; their bedroom was downstairs on the other side of the house.
"What the hell are they doing?" she said. "How can they do that?"
I shrugged in the dark. "I don't know."
"How long has this been going on?"
"I don't know! This is the first time I've seen them do it," I said.
"It's disgusting," she said. But she didn't leave; she just stood beside me, watching.
Roger was getting into a rhythm, one foot on the bed, the other on the floor, pausing before each thrust, his dick nudging against her pussy, then sliding it in, burying his dick, and then slowly inching it out. Becky gripped the side of the bed, throwing her head back with each stroke, her body shuddering, looking like she was holding back a scream as her brother slowly fucked her.
