Gabernastics - Gabernastics is when you're so mad you're just whisper-cussi

Gabernastics is when you're so mad you're just whisper-cussing to yourself like no one can hear you.

I did gabernastics in the library because I was too scared to yell.

I did gabernastics during a test because I couldn't remember the answers.

I did gabernastics in the car because my sibling was being annoying.