1. When a male has his hands down his pants for an extended period of time, while people are around. Examples include, extended periods of itching, scratching, adjusting, etc. Also, sometimes people just put there hands down there for no reason at all, while people are around. All of these can be considered fandanglin'.
2. When a core group of your friends takes part in any sort of activity and doesn't invite you along.
While with a group of friends (or people in general), and upon seeing a friend (or any male that is present) with there hands down there pants, you say "Quit fandanglin' over there".
Lets say you call your close friend. Your close friend is on his way to a party and he's with a group of other close friends. However, you didnt' receive an invite. Upon noticing this, you say "Why are you fandanglin' me?"