I understand that it is important for preparation that the emulsified soap be hot when it's lathed onto the face; but after whipping out the excess water, stirring my brush against the shave soap until the lather is the recommended consistency, and finally bringing it to my face, the lather is warm at best (from hot water from tap). The only exception is when I boil water prior to shaving and use that, but I'm afraid water that hot is bad for my brush, and that's not convenient for shaving right after a shower anyway.

What's the best way to get a hot lather on the face?