"It must be the henny" might be a triple?
it sounds like "hindu" - hindu kush is a weed strain and the hindukush mountains obviously. You can climb pretty high and also fall pretty hard at the same time.
The hindukush is a fold mountain and if the plate tectonics collide it would result in an earthquake.
I think it also might stand for shady and marshall - They don't mix well together (like weed and booze) and they're both at the same time inside his mind and he's (literally and figuratively) shaking
Also the first line after the hook: "Your dreams are gettin' fulfilled, ooh, I'm literally gettin' a chill"
Marshall won the battle against shady and now he's getting a chill cause he's on withdrawal?
Reminds me of my cold turkey days - you're just shaking/having a chill and probably going to relapse. The hindukush mountains are really big so it takes a long time to climb up and down to reach your destiny - Just like drug abuse
But English's not my mother tongue and I'm probably reading way too much into it 😂