When you feel fat and fat and that your thighs are jiggly and you feel the fat settling in. You don't want anyone to see you this fat so you don't go out. Skinny people can experience this too.
Julia: Hey, wanna like go to the mall with me right now?! Jake is gonna be there!
Brittany: Ugh, not really. I don't feel like going out today. I'm having an IFFD! I feel the fat settling in to my ass and thighs and my cheeks are growing. Jake is sooo gonna think I'm fat if he sees me like this!