The act of defecating in the upper tank of the toilet. Much like an upper decker, the texas tanker must be hard and cannot be the liquidy product of a long night of taco bell and misery. When the Texas Tanker sets sail, it can float without sinking giving off a horrid smell for days. The texas tanker should only be used on people who have wronged you in some way.

When you eat dirt for the first time and leave your family to build a shack in the woods