Breaking character. Laughing or going out of character while performing an act. Name comes form comedian Jimmy Fallon who is famous for laughing in most of his sketches from Saturday Night Live and his late night shows.
When you happen to be walking the same way as the person in front of you, but since your not following them, it means that they are following you...from the front.
Guy 1: I hope it doesn't seem like were following these people, they've been walking in front of us for like 3 blocks.
Guy 2: Naw Man, they're front following us. Stalkers...
Guy 1: Yo, have you seen those jehova witnesses last night?
Guy 2: yeah man, I reverse-followed them all day! I was un-jehoving!
Guy 1: Damn dude, you gotta stop all that reverse-following!