A meaning when you saysomething very weird or cringy or mostly dumb and you keep acting goofy about it.
My friend is Falling Off The Perc when he was shoving hot dogs in his mouth.
My friend is Falling Off The Perc for calling my other friend a terrorist because of race.
When one person loses their train of thought multiply times during conversation because they fried their brain doing too many drugs. Also falling off the train in life resulting in not fulfilling their full potential.
You asked me that twice already, you really need to take better care of yourself because your fallingoff the train.