The consuming of a Big Mac from McDonald's, and shitting it out in a diarrhea-ish manner later on that day, or the first thing next morning.
Ketchup: (yelling into the bathroom) Hey Beef whats taking so long?

Beef: Oh I just had a Big Mac man!

Ketchup: And?

Beef: Its coming out of my ass right now, and I only had it a while ago! I'm having (yet another) Big Mac Shit Attack!

Ketchup: Ouch. I feel bad for the toilet after this one.

Beef: Yeah, me too.
by RogueMan7 December 17, 2007
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