To stand in front of a gas station and/or a convince store for a long period of time. The more common store is 7-11, but it is much easier to Clerks-It at a shitty convince store that no one will care if you loiter.
"Hey Justin, I'm bored shitless. Let's go Clerks-It at the Ghandi Store."
"Goddamnit, I need some cigarettes. Let's go Clerks-It and try to get some drunk guy to buy us a pack."
"Hey, you know that 7-11 on 10th Ave, We Clerked the shit out of that mother fucker."