When a small fart is released while exercising or performing some other physically strenuous activity.
I was holding his feet for sit ups in gym, and he let out an exerfart right into my mouth! It tasted like chocolate chip cookies!
I picked her up from the bed to bury the sausage in her whispering eye and I accidentally exerfarted!
My dad is so old, he exerfarts every time he gets up from his chair.