I. When sending a pornographic link over IM, appropriately tag it sfw or nsfw.

II. Never admit to a dude's chick the existence of the dude's porn collection.

III. When you lend a dude's chick some money, the dude is responsible for reimbursement, even after he breaks up with the chick.

IV. If you're ever so lucky to find nudie pictures of a dude's hot girlfriend, you are obliged by the Dude Code to, in all discretion, share them with other dudes. (note: via e-mail or IM only!)