One who acts, talks or looks like a creeper, rapist, pedophile.. etc. Likely to touch those who are unwilling to be touched. Most pptouchers will deny that they are one when accused.
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.