You should be aware that this phrase is sometimes considered offensive. It is a pejorative term for Masturbation by a male. 'You are a jerk' - you are a person who engages in excessive masturbation, and this has a bad effect on your personality.... 'Stop jerking around' is literally 'stop masturbating and get on with what you are supposed to be doing'. However, it is usually taken much less literally, and would mean ''stop engaging in frivolous activity that only pleases yourself and get on with what you are supposed to be doing' There is a difference between accusing a person of Jerking themselves around, and jerking another around. 'Stop Jerking me around' - 'stop trying to distract or misdirect me, allow me to get reach my objective'

In my mind "to jerk around" means to mess around, to act in a non serious way. "Why don't you stop jerking around and find yourself a job?!" Hope that helps!