Mugs. Why has something so simple become so complicated?
Titanium, stainless, plastic, silicone and everything in between.
If the texture or taste of a metal mug doesn’t work for you. Neither does a cheap plastic mug, then the collapsible mugs may be the only other option.
There’s a popular small cup thing, (which is about as big as an egg cup = pointless) or the Sea To Summit collapsable one with a hard rim. This is okay, except when drinking really hot liquid and the folding section gets hot and malleable.
New to the market is the UCO option which is another idea.
Made from durable BPA free material it has a hard upper section for holding and putting to your lips. However the lower half folds inside itself, making it easy to pack.
It has a strong feel to it unlike some of the other options too. So it will stand camp life, hard washing and very hot liquids.
The best part is that it will hold 355ml, so the same capacity as the metal and plastic full size mugs. The weight is a very respectable 60gm and it feels good on the lips.