First time post: yesterday, the horn was hot to touch, just awful. I tuned it before playing (as usual), but it played out of tune horribly (sometimes I wish I didn't have my ear) - I finally thought through the physics: that my breath was actually cooling the horn instead of warming it. It occurred to me that maybe playing a metal mouthpiece (i use a Jody Jazz DV and love it), made my tuning nightmare worse. Any suggestions out there re: rubber v metal in the heat? Thanks for any feedback!