It's Just a Splash
If you understand the physics of impact in a bunker, you'll have a feel for how to play some of the specialized shots.
It's the same as splashing in a pool. If you want to create a high, short splash, you slap sharply down and into the water. If you want a longer, lower splash, you whisk your palm across the surface in a skimming motion.
Imagine a golf ball riding on the crest of those waves, and you'll understand what's at work in bunker play. For a short, high shot, you must hit down sharply, and for a longer shot, your angle of attack must be more lateral.