What do you mean by 'spark somebody up'?

The verb spark can be used to mean ignite or electrify, and English is a flexible enough language that the phrase "spark someone up" could concievably mean several different things. For example, someone could receive a flash of inspiration, a jolt of motivation, or become energized, turned on, or transformed. The words could also be slang for a literal jolt or flame, such as a flame from a lighter, or a shock from a taser.

I couldn't find a reference to tasing, but when I looked up the phrase "sparked him up" on Google books, the findings confirmed my hunch: evidently, the phrase doesn't seem to be confined to a single meaning. It can be used to mean:

Light Someone's Cigarette

He made a thumb flicking motion for a light, and I sparked him up with my Bic. ↣

Distract, Affect, or Arouse

The woman in the seat beside him was distracting as hell, and he needed to get his mind off her. It had been a long time since he'd met a woman who sparked him up like she did. In fact, as he pondered it, he wasn't sure he'd ever met a woman who affected him like she did. ↣

Energize

Maybe the caffeine in the Cokes had sparked him up. ↣

Motivate

He was a rewarded with a biscuit. Tim seemed a little miffed that Teal had worked better for me than he had for him in the demonstration, justifying it by saying, ‘I think we sparked him up with that nicer piece of food.’ And I though we might have sparked him up by our remarkably quick bonding. ↣

Inspire

He also had that wonderful casualness of giving up on a scene if it wasn't going well. If he wasn't hap, he just mumbled fast and walked off smirking. But if he liked his material and if another actor sparked him up, he could fire into life. ↣

It seems like the best thing to do is discern the meaning from the context where you find the phrase.

Without context, it is difficult to ascertain the exact meaning in your scenario.

Certainly, in British English, one can "spark up a cigarette", meaning to light it. The term could be extended to mean sparking someone up as in:

"can you spark me up please?

...although I've not heard the term used to a third party:

Can you spark him up?

One must be careful, however, because sparking somebody out, means knocking somebody unconscious:

If he doesn't shut up, I'm going to spark him out!