From your description, I believe that your breathing is similar to what we did when I studied Northern Shaolin Kung Fu Wu Su.
The way that we were taught how to breath was actually through a breathing exercise we would do every start of the class as part of our standard warm-up routine. Laying on our back with our hands lightly touching our abdomen below the belly button, we were guided as we would first inhale slowly through our noses, into our abdomen instead of our chest cavity. Then, just as slowly, we'd exhale loudly, making a "sssssh" sound through our mouths. This would be done as slowly as you can, making sure that the sound you make remains as steady and as constant as you can. At first it is difficult but quickly you gain more control over your breath and can do this even more slowly and much more steadily.
After the slow breathing, we'd repeat the process, but instead, breath very quickly and with power. We'd inhale in the same way as quickly as possible, and then exhale just as quickly making the same sound. We'd do this over several repetitions.
Through repeated practice, this helped me quickly gain control over my breathing technique.
Then, when actually practicing techniques, we would apply the same things learned through that exercise to our breathing in our techniques. When going through the motions slowly, we'd breath in and out slowly according to the requirements of the technique, in slowly through our nose, and exhaling slowly through our mouths making the same "sssssh" sound. When moving on to train the techniques at a faster, more real-world pace, we'd adjust our breathing to match.
Over time this should help train you to breath properly through your technique. This is how we trained it.