When you overload your booksack and either you or a friend intentionally 'bash' into fellow schoolmates, especially people you don't like. This is either made to look like an accident, or on purpose. Typically is determined by the recipient's social standing.
"We're about to make to make a video, we call it Hall Bashing, we don't take no prisoners, we bash your damn faces in!"
"Wow, neck and his buddies Hall Bashed my damn face in"