I was over at my brother’s place last week helping him set up a new TV in his master bedroom (he currently has a cast on one hand). After we were done, he made a dumb joke, and in response, I did a dramatic face plant on the bed. When I got up, I realized I’d left a lipstick stain on the sheet. I offered to clean it, but he told me it was no big deal, and I went home. The problem is that my sister-in-law found it and now thinks my brother is having an affair. I called her up and told her exactly what happened, but she thinks I’m lying to try to get my brother out of trouble! What can we do here?