Years ago, my ex-wife and I were at a pool party at a friend's house. It was a celebration for friends and their families so there were maybe 40 people of all ages there. My wife was wearing a modest two piece swimsuit that she'd owned for a few years. Although it still fit her well, the elastic waist of the bottom piece was worn out so she had to be careful about it dropping low on her hips while walking around.
At one point, while I was involved in a pool volleyball game she decided to take our toddler into the shallow end of the pool, sit on the stairs and watch the game. When the game was over we all headed for the stairs so she got up with our child in her arms to climb the stairs in front of us. Unfortunately for her, when she got up her bikini bottom, now wet, was too heavy for the loose waistband so it slid below the cheeks of her ass! Because she was holding our toddler in her arms, she couldn't do much about it and by the time she climbed to the top of the stairs her whole bottoms were around her knees! We were all cheering by the time she put our son down and was finally able to pull up her suit!
Although she laughed it off, she was very embarrassed and pissed at me because I cheered along with everyone else. Years later, she would still get red-faced whenever someone would bring it up and she'd be mad at me all over again. Oh well. The memory was worth it!
PS...Thanks, Delboy, for jogging my memory on this one!