Lucy - interesting about the breathing.
One of my midwives told me to breathe in slowly through my nose, and try to get it all to my tummy. Her justification was that its a big muscle (the uterus) and the more oxygen it has, the less lactic acid build up, there fore less pain.;
Not sure if it is true, but it was great to focus on something with my breathing. Interesting that you say it could prevent spewing too!