It must be hard to fish with only your bare hands! Is it true you can't even use bait? It seems like an impossible challenge!
Your thumbs are the bait. They look tasty to a big catfish. 
Wow, I learned something new today! So they bite your fingers? Do you go to a lake or a river or something like that?
lake has been the lucky spot for me. 
Catfish can get really big, too. The largest one ever caught was over 100 pounds. I wonder what the record size is for catching it with your hands. Maybe 50 pounds or so?
catching fish is a lot of fun, but when you get a snapping turtle instead it can be painful
That would be terrifying. Apparently it happens a lot when people are trying to catch catfish. Occupational hazard, I suppose. Those things could definitely take off a finger or two.  
living without thumbs is badge of honor for a noodler
Quite the sacrifice I'd say, since thumbs are responsible for almost all coordinated motions with your hands. But, I imagine it would be an amazing party story. 
it does make it a little difficult to hang on to a beer can
Oh, but there's a fun fix for that. Just modify one of those soda drinking hats with the straws coming out the sides! No thumbs required. 
Wearing one of those is like shooting your beer - once the flow starts it's difficult to stop it
Well, maybe just a bendy straw and a flat surface then. Beer is half the fun of fishing, noodling or not. 
Seems that beer is not just fun, it's essential to get a little plastered before noodling