When someone portrays an act usually on social media showing themselves being “attractive” or doing exceptionally on a trend. However one’s thoughts might differ and this is where the term comes in. “She thought she ate” meaning she thought she did so good on that trend or she thought she was hot or she thought she was all that.
sheater:- means shit eater. Someone who eats "shit"
You see a shit. You pick it up. You put it in your mouth. You chew it. You swallow it. You throw it back up.