Attilio Anthony John Wagstaffe
Try not to think about it too much ...... should come back to you if you have had a lay off....... I personally feel that too much thinking about execution of waza and breathing can be inhibiting and defeats what you are trying to achieve.....
I remember one sensei saying, forget which one, always said..... "Don't think.... Do!"
I agree with Tony. Don't think too much about it. I think it is a catch 22. You shouldn't be holding your breath, breathing should be natural. I mean you walk down the street and breath with no issues, so why would doing this be any different?
Emotionally though, we will find ourselves getting caught up in the movement and tensing and holding breath and being "high", we should relax breath naturally and be "low".
I do agree with Lynn as well on where it should occur, but again, I don't think we should be deliberately doing it or concentrating on it too much.
It might help to put your mind there to teach you to relax and to relieve tension and to help with the reconditioning practice.
I see alot of people get this weird Aiki posture breathing thing going on though and they get all stiff, erect, high sort of like they have a pole up their ass, and do this sort of big breath thing that is not natural. IMO this is way over doing things and your body should be relaxed and just move naturally for the most part.