Coughing from the stable probably indicating spliff's lit
Earl is in a bathroom stall smoking a spliff (tobacco and weed). This line invokes the dual meanings of ‘horse’, the animal and ‘hoarse’, having a dry throat/voice, without actually saying either word. Earl calls the stall a ‘stable’, which is the name for a shed that horses are kept in. Additionally, he has a hoarse voice as he coughs from inhaling the smoke.
To help improve the meaning of these lyrics, visit "Hoarse" by Earl Sweatshirt Lyrics and leave a comment on the lyrics box