Somewhere between crust and fluff. Perhaps something nasty in your belly button.
I think I have a problem! I stuck my finger in my belly button and pulled out some flust.
by Toshibi January 03, 2006
The powdery residue at the bottom of a cereal bag. It's flakey and dusty.
The only thing that can ruin my cereal is the flust.
by Sstephen September 22, 2015