Sandpaper’s roughness is measured in numbers—the lower the number, the coarser the paper. For example, if you were to sand down a 2x4, you might start with 80 grit, then work your way up to 220. Or, if you’re this guy, you can start with your hands. For some reason, this man’s hand calluses are so developed that he’s able to decimate a piece of wood using just his palms. It’s impressive, but it’s gotta make it damn near impossible to jerk off.