mapping the great lakes Share definition Flag when you gizz on a girls chest after a bj, causing it to run down and look like the great lakes. I was supposed to go to work, but I was to busy "mapping the great lakes" on my chick. mapping the great lakes by B*rad August 13, 2007 0 0 Get merch Get the mapping the great lakes mug. Buy Now — $32.95 See more merch