When I was around 14 I was going through a bunch of VHS tapes with my (much) younger sister. These were all just a mishmash of unlabeled recorded tapes that might have been a movie from TV or just old movies that we lost the sleeve for or the title rubbed off the tape/case. Well, my sister and I were bored and just checking out what's what. Popping tapes in and watching for moment or two to figure out what the movie was. Sometimes we had to rewind first, sometimes we had to fast forward. Well one of these random tapes got popped in and our stepfather was just a few feet away. The opening shot had me basically diving back at the VCR to stop and eject the tape. The video started playing with a partially dressed woman showing off her bits. When my sister (who I prayed didn't see enough of the video to recall or understand what she saw) asked what that was, I said it was just a lady showing her arm pit. I slammed the tape back into the cabinet and hoped I wasn't going to get in trouble for what just happened.
Looking back on this event as an adult, I realize I didn't do anything wrong. But boy oh boy did I think I was going to get my ass beat. Luckily my sister never recalled and stepfather never turned around.