Make him watch you mastrubate, but don't let him touch you. Better yet, do it while wearing some sort of cute "cliché" costume like a schoolgirl getup or sexy underwear.

It will make him go out of his mind with desire to pounce on you. Heck, I got hard just from writing that!

I love to tease my man!! It's a lot of fun and adds so much excitement when I know that he's hot for me...and can't wait to have me.  The best way I have found to do it is find what really gets them going and then run with it, but in very subtle ways.  

The way to get my man going is through his head..he's very visual, as are most men.  But when I know that I am not going to see him for a while, I will write him a steamy letter...something that I am quite good at.  But when I write him this letter, I focus on things that I specifically knows that he enjoys.  For instance, he loves my BJ's.  Says the best orgasm he has ever had has come from one...So I tend to focus on that.  It's all about getting into their head, teasing them with words, and mind f*ing them basically. It might sounds like games, but what better way than to mess with their head than with sex.  Keeps them guessing, always anticipicating, and definately coming back for more.  

Good luck with your little mission.  Hope it goes well.  Just find out what makes him squirm and add your own spice to it.  Be subtle..give him a chance to paint the picture in his head, then he will definately be eating out of your hand.