The word is a synonym for tummy. The specific sort of tummy, that characteristically has more fat (or Schwabbel) than muscel. It doesn't have to be a really really fat tummy. even very thin people lacking muscle can have one
" Oh my godI had so much food, my poor old schwabbelinski will grow even bigger!"
The state of being so bake that everything starts to look animated - half real & half cartoon - like the charles schwab commercials.
google search charles schwab commercial to see an example.
(tyler): yo dude i was totally schwabbin last night.
(ryan): what does that even mean?
(tyler): you ever see those charles schwabb commercials, where the people are like half cartoon half real.... well yeah i saw that in real life.