I usually apply hot hide glue with a brush. This is a tried and true method and it works very well.
There are a few situations where I find applying glue from a bottle to be much easier. Installing wooden binding is an example.
Somewhere on the web I found a tip about heating hide glue in a small squeeze bottle. I can’t remember who suggested this or on what web page I found it but I would like to thank whoever first posted this simple technique.
I prepare hide glue as I usually do but in a 1 ounce plastic squeeze bottle. I heat the bottle in the water within the glue pot. I can then apply real hot hide glue as quickly and easily as any other bottled glue.