Hey B,
my lungs are quite sensitive and I struggle to get enough in to blast off. Few tricks I use, very simple, you probably even do it yourself:
Cold water in a bong with ice cubes or even better crushed ice.
Before the first hit, hold the smoke inside the bong a bit (usualy about 10 seconds) to really cool down, as I find first hit is always strongest.
While taking hit, feel the harshness of smoke and if it gets too dense, mix it with air.
and practice a lot

happy journeys