Y'know when people say a person has some skill "under his belt"? Is that supposed to be a reference to some kind of measuring contest or something?? I think I always assumed it meant like a toolbelt, but then wouldn't we say "on his belt"? Or maybe it references a place where you can hide a weapon, like a clandestine candlestick or something?
i think it's a digestive reference. like you've eaten your skills