I find that the key to breath smoking, for me, is how I hold my tongue against the back of the roof of my mouth, forming almost a sealed chamber in my mouth.
Then, as I rhythmically breath through my nose, smoke leaks into the chamber on inbreaths, and slowly leaks out of the bowl on outbreaths. About every 4 or 5 breaths I puff the smoke out of my mouth, and then breath another 4 or 5 times and the mouth chamber fills again. Repeat.
To get the tongue position in the mouth right, say the word "egg" and note how your tongue presses up against the back of the roof of your mouth.
Hold it there, put the pipe in your mouth, light and and start breathing. This is a passive method, as opposed to active puffing. It's more about pressure changes as you breathe, filling the chamber in your mouth over the course of 4 or 5 breathing cycles rather than sipping and puffing.
I pack using the air gap method, and bowls in my Savinelli billiards last me about 45 minutes.