Let's use the Philly as a dipstick for this bath salt,
Philly here likely references a Philly blunt. They’re going to dip the blunt in the bath salt and smoke it like u would with pcp or coke. The blunt is the dipstick.
Another less likely suggestion is that Philly can actually refer to a “Philly Stack” (A roll of $100 dollar bills). And a dipstick is a tube to check urinary infections. So they’re using $100 dollar bills as a tube to take bath salt.
To help improve the meaning of these lyrics, visit “Jamba” by Tyler The Creator (Ft. Hodgy Beats) Lyrics and leave a comment on the lyrics box