When I soak my brush, I put it in my lathering bowl, fill it with hot water, put that in a sink filled with hot water, then hit the shower. When it's time to shave, I dump all the water, fill the sink again, then lather up. I keep the bowl in the sink -- a foamy island surrounded by hot water -- as I make my passes. Lather stays nice and warm.
When I want really hot lather I use a scuttle. First, I heat water in an electric kettle until just before boiling. Then I fill the lower chamber and top bowl of the scuttle and put my brush in the bowl. Then I heat more water, but this time to boiling. I dump the old water out of the scuttle and refill the lower chamber and just put a small splash in the top bowl.
The only problem I have with this method is that my lather tends to dry much, much faster than normal. In fact, I usually never have problems with my lather drying out. To remedy that problem you just need to add some more water as you shave.
You can make a "ghetto scuttle" if you find two bowls, one slightly bigger than the other, so that the bigger bowl sits on top of the smaller one. Fill the smaller bowl with hot water, and viola warm lather goodness.
I have the Dirty Bird scuttle and using it with just the hot tap water gives me great warm lather which I can lather up in the scuttle itself. It's a heavy chunky thing though, and some lather dries out quicker, but today I made up a great lather with Tabac and had a great warm shave.
Can the scuttle be used to make nice hot lather from shaving cream, such as the Body Shop's Macca Root cream which I use almost exclusively as opposed to soaps?