"I (23F) recorded my sister (27) and her husband (27) having sex in her old bedroom. My bedroom and her old bedroom at our parents house (I still live at home while I go to school) are attached by a Jack and Jill bathroom. She and her husband came in last weekend for one of her friends wedding and are staying with us for the rest of the week to visit. On Sunday, my boyfriend and I went out with friends to a Super Bowl party, and I had intended to stay the night with him, but we got in an argument, and I just didn’t want to deal with the drama, so I went back home. It was late, all the lights were out downstairs, and everyone seemed to be in bed. I went upstairs quietly. I get to my room but before I turn my light on and shut the door, I hear some muffled (male) groans, and what I know to be the sound of sucking dick. They had forgot to shut the doors from either of our bedrooms to the bathroom. I had to go to the bathroom, so I went down the hall to pee in another bathroom so I didn’t make anymore noise. When I got back, I very quietly shut my bedroom door and the door from my bedroom to the bathroom, changed clothes, got in bed, and didn’t hear anything more than some giggling and small talk for about 5 minutes. He got up, went to the bathroom, got some water, and asked her, “Did your sister come home?” She asked him “Why? Is her light on?” He said no, and she said “Yeah, no, she’s staying with her boyfriend tonight.” He goes back to her bedroom, AND STILL LEFT THE DOOR FROM HER BEDROOM TO THE BATHROOM OPEN!! Part of me wished he would have shut it, part of me was hoping he wouldn’t. A few minutes later, more giggling, some kissing sounds, and then she started making some noises we are all familiar with, he was clearly returning the favor. I pulled my phone out, walked up to my bedroom/bathroom door, and slipped the phone just under the gap at the floor and hit record. I got back in bed. I could hear them just enough that it was turning me on, but I couldn’t hear nearly as much through the door as I heard later when I listened to the recording, especially since the phone mic was under the door. Holy Shit. Side note, eerily, my sister and I make some of the same sounds when we’re fucking/getting fucked. So, here I am laying in bed just listening to him eat her like a peach. To make things worse, I’m starting to throb and getting wet now too. I hear her let out a wail….. and now I’m in overdrive. Girls, you know I’m not wasting this opportunity right? I take off my T-shirt, pull my panties to the side, and get to work. I’m not sure how long they’ll be going, so I get the job done, and hold the moan. They’re not done. Fuck it. I peel my panties off, and get back to it. By this time, he’s really laying it down and I came again, not making a peep. Anyway, when it sounded like they had finished I quietly got back up out of bed, legs still quaking, and got up close to the bathroom door. I could hear them walking into the bathroom and in a panic, snatched my phone back from under the door. I laid in bed last night with my headphones on re-listening to them, fantasizing it was me getting filled up. She told me after they first had sex when they were dating, he was “BIG”, but I didn’t know how much of that was just talk or if he was as big as she said. After listening to the recording, I definitely believed her. As if that wasn’t enough, I accidentally saw his dick THIS morning in the mirror when I went to my room to get a book for my mom. He was getting dressed in her bedroom, but from where he was standing, the mirror in the bathroom gave me the perfect angle to see in her room. No wonder she married him.