So this was a few years back, my gf and I were hanging at my place and it was late at night, so my parents went upstairs and me and her were downstairs and decided to watch a movie. At some point we pause the movie to make some popcorn, and we heard of something banging the wall, I go check it out and as I walk down the hallway and then I hear the sounds of moaning. I peek my head through the doorway because they left the door open and saw my parents fucking! I was shocked and stood there for a while, and it was maybe a few minutes when my gf comes up and sees what’s up and she makes a sound but I covered her mouth and my parents stop for a sec and then continue. Me and her eventually go downstairs and react for a bit, but then she tells me she got a little turned on, so eventually we fuck on the couch and hit resume on the movie to cover up our sounds of fucking. We cleaned up afterwards and the next morning during breakfast we acted like we heard nothing upstairs lol