Top definition
To consume more than one McDonald's Big Mac in one sitting. Although considered by most to intially seem harmless, can usually result in increases in heart rate, blood pressure, cholesterol, and depression-like symptoms.
Guy 1 - "Hey, isn't Jeff coming out to the bars with us?"

Guy 2 - "Nah, man. He was mac-ing out earlier today so he's done for a while."

Guy 1 - "Damn, son. Hope he's okay."
by Ronald J. McDonald August 20, 2013
Get the mug
Get a Mac-ing Out mug for your Facebook friend Jovana.