I guess i'm just the opposite of you then. I've only been with one guy who wasn't circumsized.
Do you mean that there isn't any foreskin to play with, is that it? Because i've heard that uncircumsized men get a lot of sensation from the foreskin. I don't really know though, since I don't have a penis.
It's hard to describe, personally i'd rather give oral, but if you guys are into handjobs then that's all good too. Ask him what he likes... Better yet, masturbate in front of each other and take mental notes. I just re-read that, it sounds like i'm joking but i'm not, i'm totally serious.. It will help.
It's pretty simple. You just have to grip the penis low and hard enough so that the skin beneath the head will glide up and sort of emulate foreskin as you move your hand. You don't want the rim of the tip of his penis to come into direct contact with your skin as you move, because it will create painful friction. Just have him show you, if he's ever masturbated, he'll know exactly what to do. Just don't grab too low or you'll stretch the skin from the base!
Go to the local drugstore and buy a tube of ky gel. It's a lubricant designed to deal with this problem.
Cover the head (the glans) of his penis with it. He'll likely enjoy that experience. And then get to work. Remember that many men are insecure about their penis. He'll want to hear you say nice things about it.
While the real truth is that most penises are pretty strange looking, and a color you wouldn't paint your bedroom in, it's the only one he has and he won't refuse to hear you say that it's warm, and strong, and exciting, and looks like it would be really enjoyable inside you. Don't say that last bit unless you want to find it inside you pretty soon.
And remember that many - most - men enjoy being touched elsehwere too. He'll like you to stroke and squeeze his balls a bit, he'll enjoy feeling your fingers stroking the inside of his thighs. If he's hairy, he might enjoy being shaved - and he'll pretty surely enjoy helping shave you. Don't waste too much time on his nipples - his don't feel to him even remotely as interesting as yours do. Squeeze his butt, too - lots of men like that but can't somehow bring themselves to say so.
You want to pleasure him? Try kissing him thoroughly and with full long tongue, and then start kissing and nibbling all his skin from his face down to his waist, and then from his feet up to his waist, and then start out on his penis which by that time will be firm and erect and ready for you. And suggest to him while he's at it that you are a complete woman, and if he doesn't know what to do with all the frills and delights you keep in your vagina you can show him, and remind him lovingly that women dance to a slower beat than men so he doesn't need to be in such an all-fired hurry.
With any luck, you'll both finish together and it will be good, and the world will have two happier people in it than it had before you started.