I never got caught per se but I came close one time getting a BJ.
We were up in my room (door open) while our respective parents were outside socializing. One thing led to another and I wound up with my zipper down and...well you get the idea. I heard the distinctive creak of the top step and knew I would have less than five seconds until we were discovered. I could not stuff it back in that fast so I thought fast, grabbed her and sat her on my lap.
Mom peeked in to tell us that the food was ready and gave us the strangest look...she was bright red and giggling like mad sitting on my lap! She never found out exactly why though
Brian