Very, very carefully! Sorry, I couldn't resist.
Try inverting your bezel so that the tips are down and somewhat
protected from the heat. Even then, I sometimes get a little
slumping. It's a delicate torch act. Another little heat shield aid
is to coat the bezel tips with WhiteOut (the NON-flammable kind!!).
Remember to fuse in low light so you can see that fuse-flash and
pull the heat off immediately.
Judy in Kansas