With my sister-in-law

It all started about three years ago, shortly after my wife and I got married. Her sister, Carla, had always been the “homewrecker” type, the one who flirts with anything that moves. At first, it was looks that lasted a second too long, “accidental” brushes against me when she passed by at family dinners, compliments about my physique that crossed the line from familial to something else. Truth be told, I played dumb at the beginning, but my cock always voted in her favour. My wife, innocent as she is, only saw the normal camaraderie between in-laws.

The first proper encounter was at a family party. We were all dancing, and in a moment of chaos, Carla pressed herself against me to dodge a drunk cousin. I felt her whole body against mine, her tits crushed against my chest and her hand, which just so happened to land right on the bulge of my erection in my trousers. She didn’t move it away immediately. On the contrary, she gave a little squeeze, looked me in the eyes with a mischievous smile, and whispered, “Oops, sorry, didn’t know you brought reinforcements.” That night, I had to lock myself in the bathroom and wank like a teenager, imagining it was her hands milking me dry.

From there, it was a slippery slope. We started texting, first with silly excuses, then the messages became full of double entendres and “innocent” photos. Her at the gym, sweaty, in those leggings that moulded her perfect arse. Me, “accidentally” sending her a shirtless photo after a run. The tension was a living animal eating us up inside.

The first time we kissed was at her flat. My wife was away on a business trip, and I went over to help her build some furniture. We ended up sweaty, having a beer on the sofa. Suddenly, a heavy silence fell. I leaned in and stole a kiss. She wasn’t surprised. Quite the opposite, she devoured my mouth with a hunger that made it clear she’d been waiting for this a long time. We ended up shagging right there on the sofa, like animals. She climbed on top of me, guiding me inside her with one hand while covering her mouth with the other to keep from moaning too loudly. She whispered in my ear, “I’m tighter than my sister, aren’t I? Tell me.” And I, possessed by the filth of it all, confirmed it between gasps. It was quick, dirty, and incredible.

I thought the madness would end when she got a boyfriend a few months ago. But it was the opposite. The dirty slag became even more obsessed. Now every meeting is riskier and hotter. Once, she came over when my wife was at the supermarket. We didn’t even make it to the bedroom. I fucked her against the fridge door, with her boyfriend waiting for her texts on the mobile she was holding. As I thrust into her from behind, gripping her hips and listening to her arse cheeks slap against me, she was sending him a voice note: “Baby, I’m almost finished with work, miss you.” I shouted when I came, and she turned and kissed me to shut me up, swallowing my groans.

The obsession is properly sick now. She sends me photos of her soaked knickers after we’ve been together, tells me she masturbates thinking about me when she’s with her boyfriend, that she likes feeling his penis inside her but imagines it’s me fucking her. A few weeks ago, at a family gathering, she sat opposite me and, under the table, unbuttoned her jeans and touched herself while we held a normal conversation with the whole family. I could see her breathing getting faster and I couldn’t do anything but watch her, my cock hard as rock, wishing I were the fingers she was pushing inside her cunt.

I fear the day this blows up. My sister-in-law is obsessed, and even though her body is a temple – perfect natural tits, a high, firm arse, a waist that begs to be grabbed – and every fuck is an explosion of pure filth, I know this can’t end well. But when she calls me and says, “Come over, my sister’s gone out,” my brain switches off and I can only think with my cock. It’s a dangerous addiction, and the worst part is that she doesn’t care about anything anymore. She wants more, always more, and I don’t know how far I’m willing to go.