Check to see if you have a hobby shop in your area. Most carry these in stock, and it helps support local business rather than Scamazon.

But also be prepared to have your mind blown and maybe pick up a new hobby. 😂

These bags are what many rc hobbists use to store and charge lithium in. There are many different form factors (and price points) to pick from, but they all work to suppress the potential flames and vent off the smoke in a safer way than it just venting in open air.

I have had a battery vent off violently after an rc car I had hit a telephone pole guy wire sideways at 70mph, and it is indeed something you want to contain should it happen indoors.

Best practice is to just be present when charging, and use a bag if you run cheap/old batteries. An old metal toolbox or something would likely work as well, just anything to keep the flames down.