1. A fast-moving, no-stops train on the Brown Line.
2. A gigantic turd that tears your sphincter to shreds on the way out. Often comes without warning. So called because of a faint resemblance to a speeding subway car.
Aw man. I had a Brown Line Express this morning. I looked in the toilet, and it was actually the size of my wrist.
by Lady Csyde June 16, 2007
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