I like hifistud's term:
Personal
Inhalation
System
Solution

... but there are circumstances in which that might be considered improper.
It really would depend on the type of "legal trouble" you are in. 'E-liquid' certainly is the generally accepted term. The liquid used in the innocuous Wizard Stick is called 'fog juice'. If challenged when
vaping in public, I sometimes refer to my PV as an 'inhaler', so 'inhaler refill' might work.
Variations on juice, fluid, solution, liquid, glycerin (if it's VG) might be helpful again, depending on what you want to accomplish or avoid.