Brother was playing video games

This happened when he was in his mid 20s. I was sitting on the couch reading and he was sitting in a arm chair playing a video game. I noticed him wiggling and he started pinching himself. I asked him if he was going to have a accident and he just shushed me. After a bit he was pinching himself hard but a wet spot appeared. He let go of himself and mumbled he peed a little bit was ok. After the next game he jumped up holding himself and ran for the bathroom. When he got in there I only heard a few drops go in to toilet. When he came back his shorts were wet and when I asked if he peed his pants he just showed me his shorts and then returned to his game.