A travelling corporate presentation. It's usually a bunch of weary road warriors travelling town to town shilling some new product or tired update of the same old product.
Probably derives from the three-ring circus act where ponies prace around the ring while little dogs stand on their backs and bark.
Usage: derogatory. "Yeah, I gotta do a dog and pony in Regina, Medicine Hat and Moose Jaw of all places."
NRT