I have grown (in addition to the usual self seeding _B. liniflora_ in
cultivation) _B. gigantea_ and the two strains of _B. liniflora_ Allen
Lowrie introduced from Darwin and Kununurra---I believe the latter is
now called (having been appropriately described in the literature)
_B. liniflora ssp. occidentalis_. These latter three were very reticent
about producing pollen. A tuning fork worked well with these plants. But
I was also able to induce pollen release in all three forms by simply
dragging a toothpick over the anthers several times. The pollen would
accumulate on the petals and could then be removed. By watching where
the pollen accumulates and changing how you hold the flower, you can have
the pollen accumulate on your thumb and then remove it using a toothpick
and pollinate the plant.
I found the toothpick more convenient. And it tickled less.
Barry