Gravity-affected blocks change themshelves into falling sand entitiy when placed on top of shulker

Sand, anvil, etc will turn into an entitiy when placed on top of shulkers, and can be stacked up to 2 blocks. Doesn't matter if the shulker positioning was sideways or straight. You can place the block by making a platform above the shulkers, to make it falls directly towards them.

If you keep placing the block for a while, it will get broken, it may fall into the shulker, or to the side of shulker.