Literally bumping heads.
You see, things that we consider to be peculiar, or awkward are typically things that don’t happen very often. If they happened all of the time, we would become used to them and therefore not find them interesting anymore. I’m not sure if many people can relate to this one, but I’ll give it a shot anyway.
Sometimes it happens when you’re about to take a picture. You both lean toward each other and Bump! there it is.
It used to happen to me a long time ago, when I was a younger kid and I had a head that used to move around a lot. While playing games, trying to read a book on a table at the same time as someone else, and once it happened while I was running toward the restroom sink to get soap (we used to race. Hey, I was like 6 years old, its O.K.)
But every single time it happened, I remember not knowing how to react. I’d apologize but then what? It hurt both of us. Every action has an equal and opposite reaction. I felt the same force. The scene would end with both of us holding our foreheads and looking at each other in the strangest way, looking for something else to talk about besides the bumping heads thing. Oh childhood, childhood.