Swimmer's Bump

I went swimming today at the local YMCA. I practiced all of the tricks I learned from my friends--dead man's float, holding my breath underwater for 30 seconds, paddling, kicking, screaming for help, all the good stuff. I even swallowed some pool water. I remember the last time I was in a pool, I tried swimming by dunking my head underwater and kicking my legs to see how far I would go. It actually worked pretty well and I even reached the other side of the pool. I know this because my eyes were closed and I was not holding my hands out in front of me so I bumped into the pool wall headfirst. I didn't hit hard, but I did feel my teeth rattle and I was left with a tingling sensation on my forehead for the rest of the day. Swimmer's bump, I called it. I mean, if we can have swimmer's ear and tennis elbow, we might as well have a swimmer's bump. Although I'm not sure anyone else gets swimmer's bump other than me and people fool enough to dive headfirst into shallow water. Or into a pool without any water at all.