The word "invite" inherently has a sense of inclusion. By contrast, the aftervite is done after someone who is not originally intended to be invited to an event discovers its existence and is invited out of obligation.
Dude, I totally had to give Bob an aftervite to Melissa's surprise party. He heard about it and called me to see what what up.....sorry.
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.