My aunt and uncle (as do their other evangelical friends) use the term a lot, and possibly incorrectly, before I ever saw the Fit Club event too. I think it just refers to any feelings that are too earthly, vs acting in the holy spirit all the time. Any time you get too hung up on anger, money, sex, fun, awesome stuff, you're "in the flesh". They expect themselves to be above those sort of things all the time, or at least recognize when they aren't I guess - I think their basis on what is considered sinning is a lot more critical than the bible says. So Tom was at least in my experience using the phrase correctly, or in the common form rather.
This is the same aunt and uncle mind you, who cook a cake on Xmas and light candles (sadly they don't add 2K+ candles to it though) and sing happy birthday to Jesus every year too.
*SHRUG*