The state of being in a very fat nap, usually lasting between 5-40 minutes. Typically very obese people have experienced this phenomenon, but it can happen to healthy people. Also people who are fat schlump tend use anything from a Cards Against Humanity box, to a water bottle as a pillow, and can sleep anywhere available at the time.
Patrick: "Yo, wheres Victor?"
John: "He's over there, and he's sleeping on my trombone case!"
Patrick: "Damn, he fat schlump."