This happened when I was 18 and waiting for a bus. I was wearing really ripped up jeans and as I went to flick the ash off the end, the lighted tip caught on the edge of a tear in my jeans and rolled down the inside of my leg. It burnt so much hair that smoke was coming out the knee of my right leg. So there I was hopping up and down patting my leg, with smoke billowing out - and the bus came along. It gave my fellow passengers some entertainment at least!
Anyone got an embarrasssing moment they want to share?