Hi tatakata,
I will post a link to the kind of pectoral stretching I was takling about just to give a reference point. When you are doing the stretching try doing the breathing at the same time. It will help you keep track of the timing of the stretch and also give you some information for how much the stretching is helping your breathing.
As far as tounging goes I believe that good tounging is simply an interuption of great air flow. I do put it in my warm up, but it largely depends on what I am playing at any given time. When I do add tounging to my warm up I try to do it later in the warm up so that the air is really moving well.
I hope that helps a little.
Here is the stretching link.
Pectoral Muscle Stretch
Andrew