In complement to Cristi's dice dare you could do this one from Strawberry:
http://www.getdare.com/bbs/showthread.php?t=7819
Perhaps you could wear a shirt & tie over it if you can get a hold of them
And why not put a sock in your underwear to create some kinda bulge?
And to make the experience even more complete, try to act as "manly" as possible by doing those kinda things guys do like scratch your "nuts" or laugh at your own jokes, etc. Just to make this a lot funnier...
