Fat and sassy Adjective: Happy, elated, exuberant, in a fine state physically and emotionally, couldn't feel better, fit as a fiddle. www.urbandictionary.com

Having read the other answers, I would say that this term means different things in different cultures. In my culture it is used often and usually refers to a state of mind, rather than a physical condition. "Fat" is often used to mean contented. "Sassy" suggests confidence and usually means overly confident or arrogantly confident. Examples: "Considering my high score on the midterm exam for my English class, I am feeling fat and sassy about taking the final exam." "With all of the attention the boys are giving her, Jane has gotten a fat and sassy attitude."

Usually a woman who doesn't care about her weight would say: I'm feeling fat and sassy [ I don't care if I'm overweight as I still feel stylish/ good about my appearance]

I have no idea, but it sounds difficult to clean up afterwards.

I'm feeling* Well fat means "big" or "full of fat", and sassy means rude or disrespectful. So you're basicly stating that you're feeling fat and rude!