Once when I was 14, was caught in the office downstairs and didnt get a chance to delete the history so parents saw everything I was looking at. Was able to play it off as a email bomb, telling them I just clicked a link and all these images kept opening up. So saved me coming out than and there.
When I was 18/19 mom walked in on me late one night, dunno what she saw if anything
This past December, my ex's sister walked in on us while having sex, with my legs up in the air, and I hung out with her after that though it was never mentioned. Granted she hardly spoke English so we didn't talk much. His family was very religious, so was kind of awkward, meh
Most recently came home from a club with a guy, I was wasted didn't lock door mom walked in to ask if I was home and she didn't see the guy next to me. We were both fully clothed, so not much to see but yeh...sums up my horror stories