From the story of Attack on Titan, Rumbling is a means of global genocide by unleashing the millions of Colossal Titans trapped within the Walls of Paradis, used primarily by Karl Fritz as an ultimatum against Marley and later used by Eren Yeager as retribution against the world.
A fart with both volume and magnitue enough to render the "farter" unconscious for a few moments.
Bert: Pull my finger.
Ernie: *tug
Bert: **explosive fart noise**
...Bert giggles and falls to the floor in an unconscious heap...
Mary: (running in from another room ) WHAT WAS THAT NOISE... AND WHAT THE FUCK IS THAT SMELL ?!?!
Ernie: (choking and gasping for air) ....Rumbling Fadooka!!
Fiddling with your genitals while doing something mundane and inane such as:
- Mid conversation with a casual acquaintance
- Queing in the bank to withdraw money,
- Confessing in church
- Collecting your child from preschool
S.C.R (Sub-conscience Crotch Rubbing) is not a serious psychological ailment but it can lead to distress and situations of awkwardness and sexual embarassment