A fly girl who knows what's up.
Also, one who never fails to impress when asked about knowledge in the following categories: Harry Potter, Hilary Duff, Pokemon (old school and new school), or Sailor Moon.
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.