It is possible to place a pointed dripstone on top of another pointed dripstone with a player on the edge of the lower pointed dripstone, even though this changes the hitbox.
This is probably best to explain in video form: https://youtu.be/HUN5w-YniEY
At the end of the video, I attempt to sneak, but this is not possible when inside of another block, so nothing visibly changes.
- Place a pointed dripstone on the ground
- Sneak and move to the side of the dripstone
- Place another pointed dripstone above the bottom dripstone
- Notice how the hitbox of the dripstone expands, and your hitbox is now inside of its hitbox