The reason you’ve never seen or read about how I carry my street cash is because I rarely if ever put them in a wallet, card sleeve or even a money clip.
It may seem disorganized and counterintuitive but the way I carry cash is as loose bills, split into 2 pockets.
The first, primary and most used set of cash is placed in the same pocket as my card sleeve, my “money pocket” – nothing else goes in here. I like being able to flip out just my cash when needed, with each bill sequentially organized and freely organizable.
This is particularly useful when working with foreign currency to get a full view of the bill design, to verify the denominations – for smooth transactions.
The secondary set of cash is placed in a less accessible and therefore less used pocket. It’s just a few bills of higher denominations, for a back up.
This adds side security for loss and pickpocketing, as well as having the function of a “decoy wallet”.