Most strength movements require bio-mechanical breathing where inhaling is performed during the eccentric phase of a movement, and exhaling is performed during the concentric phase.
For example, with a Bulgarian bag shoulder press you would inhale during the lowering phase and exhale during the lifting phase.
For dynamic Bulgarian bag movements that involve spinning and swinging, try to exhale when the bag is heaviest and inhale when the bag is at it’s lightest.
Breath as calmly and naturally as possible with a rhythmic inhale through the nose and an exhale through the mouth.
For example, during a side swing, exhale when the bag is heaviest during the bottom portion of the swing and inhale when the bag is lightest when it’s at the top and dropping towards the floor.
When breathing focus on your exhales and let the inhales take care of themselves. If you focus on inhaling, it’s easy to hold your breath which we don’t want to do.
Some movements require an extra breathe, for example swipes. During the swipe there are two acceleration phases (the upswing and the front cast), at this point of the movement exhale with the exertion. There are also two phases where the bag is almost weightless (the downswing and during the pullover movement), at this point inhale.