buttcrack in public

It happened yesterday morning; I was wearing low-rise jeans and a black top that ended at my navel. I went shopping with a friend who doesn't really like it when I expose my butt crack in public. We walked into the store; my jeans were already riding low—about four inches of my butt were showing—but I didn't notice a thing. We wandered through the aisles looking for something, but found nothing. I bent down to look at an item, and suddenly seven inches of my crack were exposed; a lot of people saw it and were disgusted, and my friend, who was standing behind me, was shocked that I was showing so much. She tapped me on the shoulder to tell me my crack was visible and that it looked awful. I pulled my pants up a bit, but not all the way. Afterward, we headed to the checkout, but everyone could still see my crack, and my friend was still embarrassed. Once we were outside, my shoelace came undone; I bent down to retie it without realizing that my pants were now exposing eight inches of my backside, and my friend was taking a picture of it.