Haha, the only time we ever got caught was late one night when my little one's sister came home from college unexpected and just walked into our living room (we have our own living room separate from his parents, but at the time she had to walk through it to get to her room).

But luckily for us, at that point all he had were his hands tied together, not to anything, and we had enough warning to grab a blanket to cover ourselves, so when she walked in on us all she saw was her brother and his girlfriend naked on the couch under a blanket. She still flushed pink, said nothing, and hurried out of the room. Sadly that meant we couldn't continue, since she was just a room away. That was frustrating.

Though another time his sister had a wildly loud party in the back yard and we took advantage of the noise for good cover. Whipping him with thirty people outside was a hell of a rush, even if the door was locked. *grins*