Noun: An incident involving two chodes in which said penises, either intentionally or through sheer coincidence, bump into each other. The chodes do not have to literally bump and repel; merely rubbing against another chode constitutes a bumper chode event.
Please take note that this definition utilizes the proper (and more comedic) meaning of the word "chode," that is, a penis wider than it is long.
I got real drunk and played a game of bumper chodes with Ryan last night.
I was trying to get into the bathroom at the club when I inadvertently played bumper chodes with some random dude.