I still can't believe I hit record that night.
My voice was shaking when I started talking into the mic, but the second I heard my sister's soft moan come through the headphones later, I knew there was no going back. I'm twenty-eight now, she's twenty-five, and we've been sneaking around for almost a year. It started with late-night talks after our parents went to bed, then turned into something hotter the moment she admitted she got wet listening to me jerk off through the thin wall between our rooms.
That first time we crossed the line, I left my phone on the nightstand with the voice memo app open. I told her what I was doing. She laughed at first, nervous, but when I pulled her onto my lap and slid two fingers inside her, she stopped laughing and started whispering my name like a prayer. The audio picked up everything: the wet sound of my fingers working her, her breath hitching, the creak of my old bed when she finally sank down on my cock.
I listened to it the next morning while she was in the shower. Her voice on the recording sounded so filthy, so desperate. "Don't stop, big brother, fill me up." I came harder than I ever had just from the sound of her begging. After that, recording became our thing. We'd wait until the house was quiet, then I'd start the app and we'd go at it like animals.
Last week we got bolder. She came into my room wearing nothing but one of my old t-shirts. I was already hard from thinking about her all day. She climbed onto the bed without a word, tugged my boxers down, and took me straight into her mouth. The mic caught the sloppy sounds, her gagging a little when I pushed deeper, the way she moaned around my shaft like she couldn't get enough. I reached down and held her hair, guiding her, telling her how good her tongue felt. When I pulled her up and flipped her onto her back, she spread her legs wide and begged me to fuck her raw again.
The audio is dirty as hell. You can hear the headboard hitting the wall, the wet slap of skin on skin, her whispering "cum inside me" over and over while I pounded her. I came so deep she was dripping for hours afterward. We listened to the whole thing together the next day, lying naked in my bed. Her hand was between her legs the entire time, rubbing slow circles while my recorded voice told her how tight her pussy felt. By the end we were both panting and she climbed on top of me for round two without even turning the real recorder off.
It's become addictive. Sometimes she sends me short clips she records on her own phone when I'm at work, just her fingering herself and saying my name. Other nights we set up the mic on purpose and role-play like we're being recorded for someone else to hear. She'll call me "big brother" louder than usual, knowing the audio will pick it up. I tell her how wrong it is, how we shouldn't be doing this, and she gets even wetter. The contrast between our filthy words and the creaking mattress always pushes us both over the edge.
Last weekend we almost got caught. Mom knocked on the door while I was balls-deep in her from behind. We froze, breathing hard, my hand clamped over her mouth. The recording caught the muffled knock and our panicked silence. The second Mom walked away, I started thrusting again, harder, chasing that rush. She came so violently the sheets were soaked. We both listened to that part later and laughed, shaky and turned on all over again.
I keep the files on a hidden folder on my laptop. Sometimes I play them at low volume while she's at work, stroking myself to the memory of her voice begging for more. The audio never lies. It captures every gasp, every wet thrust, every time she calls me by the name only she gets to use in that breathless, broken way. We both know it's wrong, but the risk makes it hotter. Every new recording is a little longer, a little dirtier, a little closer to the edge we keep promising we'll never cross again.
Tonight she's already in my room, lying on her stomach with her ass up, waiting. The phone is recording. I press record and the little red light blinks on. She looks back over her shoulder, smiles, and whispers, "Tell them how bad you want your sister." I don't need to be told twice. I slide into her and start talking, letting the mic catch every single sound we make. The story keeps writing itself, one filthy moan at a time.
