Another brief topic in the embouchure chapter for Farkas in The Art of French Horn Playing was that of breathing in relation to the corners. It is something that he realized that some students would have to practice to make completely comfortable. He notes “When we breathe while playing we properly keep the lips on the mouthpiece and quickly stretch the mouth into a wide smile, at the same time opening the corners of the mouth and inhaling deeply through those open corners.”
For sure this is topic some players need to think about, as you can hear the sound of the air going in through the too-small opening of the lips at the corners of the embouchure. But how to best achieve a bigger opening?
Frøydis Ree Wekre in Thoughts on Playing the Horn Well makes a point of stating a somewhat opposing view to Farkas on this topic which for some players is certainly the answer. She feels that the corners are not stretched into a smile, but rather are relaxed on the inhale.
RELAX your face quickly and totally in every possible mini-second of a rest, especially whenever you inhale. No smiling when inhaling! Fear of not re-finding the right lip position for the next tone keeps many players away from this type of super-quick-relaxing. In my experience this fear is without reason for the most part. You will find your position for the next tone very quickly if you trust that you will find it…and of course if you do practice quick lip-relaxations regularly.
Worth mentioning also at this point is a topic I don’t think is mentioned in any classic method but some teachers advocate for. I have heard it called “guppy breathing,” it is where you drop the jaw — fully disengage it from the mouthpiece! — on the inhale. Advocates would note that you can get in a very large quantity of air in quickly and quietly by this method, if you are comfortable with it.