MacDump
The act of taking a crap in a convenient MacDonalds toilet, with or without purchasing food, whilst en route to any venue likely to have either no toilet or one so foul you would prefer to avoid using it.
On arriving at a music festival: "I stopped off on the way for a MacDump as the toilets here will be knee deep by now."
I'm going to take a MacDump while I'm here, Steve's bathroom is freezing.
I'm going to take a MacDump while I'm here, Steve's bathroom is freezing.