I was once talking to a girl who liked me - I was kind of meh for her at the time - and then the other girl in front of us sits down. Now I REALLY was just looking at the floor because I was bored of the conversation, but when this girl sat down her thong went about 1 inch above her pants. I didn't notice the thong so i just kept looking down. As soon I as a see it I realize that the girl who I was talking too is going to think that I've been starring at this thong for a 30 seconds. so I kind of panic, try to take in as much of the thing as I can then look up and smile, like I was paying attention to the conversation the whole time. Needless to say the one girl was kind of meh for me after that, lol.
The moral of the story its worse being caught by a different girl than the one your looking at.