After yesterday's post, I updated my Facebook status and said something along the same lines (only shorter), and that breathing and not gripping with my knees would be good to practice more when riding Bar.
Several of my horse friends suggested humming (or singing) while riding as a way to both soothe myself and keep the oxygen flowing--especially to my brain. Katie says she told me about humming a long time ago, but apparently I forgot.
So tonight I tried it, and lo and behold, it actually worked! It also made me laugh, which probably didn't hurt either. Bar is used to me singing to him from the ground, and seemed okay with it coming from the saddle, too. He was especially okay with the "Jess is breathing and not squeezing me with her knees" aspect of things.
So the humming experiment will definitely continue. More later.