Brew an Awkward Potion in a Brewing Stand
Add Phantom Membrane to the Awkward Potion
Wait for the brewing process to finish
Optional: Add Redstone Dust to extend the duration
Optional: Use Gunpowder to make it a Splash Potion of Slow Falling
Optional: Use Dragon’s Breath on the Splash Potion to make it a Lingering Potion of Slow Falling