You're most likely really fucking bored in class, and instead of going to cool math games, you type this instead.
Person 1: Damn I'm bored
*spams f and j repeatedly*
*fjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjfjf*
A trip to a grocery store, convenience store, or gas station for the sole purpose of buying an excessive amount of junk food and sugary drinks, usually with friends. A chud run often happens late at night and ends with everyone involved hating themselves afterwards.