A seemingly never ending period of extreme discomfort or boredom.
As opposed to a period of time that is simply extensive, "slow as a hard shit," embodies those agonizingly long stays on the loo, white knuckled on the handicapped bar, when you walk away bow legged and with broken blood vessels in the eyes.
Citizen 1: Nah man... my connection was slow as a hard shit. The movie would only load a few percent at a time... I know all too well how long those endeavors take!
Stoner 3: Dude maan.... holy shit.. 2, you see 1 takin' this bong rip man?
Stoner 2: He's slow as a hard shit, but damn mann... this shit is historical.
Stoner 1: ::smiles lazily and slumps back in his chair, with his rumbling stomach being the only sign of life::