What is the proper way to suck on a dick? Do you just put it in your mouth and move around your tongue? Or do you actually try to suck on it like sucking in your cheeks?
Think of it like a lollypop, but make a concious effort not to use teeth.
If you don't know what you're doing, this will be more pleasurable for him than you trying (and inevitably failing) at giving a good BJ.
Watch some BJ videos, and i'm sure there are written guides out there. As a man, my recommendation is to take it out every so often and just lick up and down the shaft. Press your tongue hard against the bottom of the shaft as you lick up to the tip. Toss in some deep throats if you can. Make a conscious effort to avoid tooth-on-dick. And either take a body shot or swallow, don't take it in your mouth and dribble it all over his dick/crotch.
God speed, you slut.
Practice on one of your fingers. You're trying to create as much sensation on the skin as possible so find what works best.