When someone ejaculates in another person's ass and doesn't stop, mixing the jizz and feces into a buttery substance. Afterwards, the person churning pulls out and wipes the "butter" on the cheeks of the churned.
Jon: "Yo! I'm going to be Buttering the Biscuitstoday!"
Davie: "Nice!"
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.