Why are we asking?

You can´t write a letter on the sky, you can´t write numbers on the water...

Harada Roshi

I am not quite sure what you mean by "controlling your breath". If you mean to align your breathing, the breath aligns itself, it is not you doing it. Try to imagine that your body is like an empty pipe- The exhalation passes through an empty pipe like the wind blowing through. When you let the breath flow out in this way, the place below your navel becomes flat. When you cannot exhale any further, let the inhalation follow naturally, entrusting to natural inhalation with a wide feeling.