Mex-Lax Share definition Flag When you are constipated and need the help of Mexican food to clean out the pipes "Hey John, you want to go to Taco Bell after class? I need some Mex-Lax, I'm a little backed up." Mex-Lax by LarryChicken December 16, 2011 0 0 Get merch Get the Mex-Lax mug. Buy Now — $32.95 See more merch