Play with his balls as you give him fellatio, and he'll be in heaven. You could even try taking one at a time into your mouth and gently rolling it around.
But here's the good news - he likes it. He knows it intimately, he makes love to it, and he sees it as a thing of beauty; he doesn't look for the flaws in it, like you might be tempted to do. So he'll love watching you undress, and if you add a little innocent seduction into the process, he'll get turned on and show you how much he appreciates your body when you do make love.
It might be man on top for the deep penetration and feeling of dominance; it might be rear entry for the sheer pleasure of fucking you from behind; it might be woman on top for the pleasure of lying back and enjoying the ride. Most likely, it's all of them!
But there will be ways in which you can make it even better for him, perhaps by squeezing his penis while he's inside you, or wrapping your legs around him when he's on top. Take the time to find out what turns him on, and he'll show his gratitude both in and out of the bedroom!
For example, a man's nipples are likely to be just as sensitive as yours - so encourage him to let you play with them. Some other places to stroke, tickle and lick him: It hints at penetration and breaks down barriers to intimacy and familiarity. So see what happens if you press your buttocks up against him in the night, or if you press your hot vulva against his cock as he slumbers.
Move your hips around a little as you do this, and he'll soon be raring to go. This might be best reserved for the nights you don't have an early start next day. But the good news is that there is some nice erotic stuff around that isn't abusive to women. Sharing a sexy DVD before you go to bed can really add a spark of passion and excitement to your sex.
For example, try different sex positions. If you usually have sex with him on top, roll over so you're doing it on your sides, facing each other. If you haven't tried woman on top, get up there and ride him.
If he likes rear entry then let him enter you from behind while you lie in the spoons position on the bed - that's more intimate than rear entry but probably just as exciting for him. Or take the initiative and seduce him in the kitchen. If you tell him to "do this to me now" when you're both enjoying sex, he's most likely to come there and then!