Boys:
Cop a feel every chance you get
Special emphasis on clamping a hand on her butt
Act guilty when she slaps you, but always do it again
Act all priestly while subtly trying to seduce any girl that comes along
Tell the owners of the fanciest inn in town they have a black cloud of ill-omen hanging over their business, and once you "dispel" it treat your girl to a free, fancy dinner!
Hit on everyone of the opposite sex, including your girl
Dress in black robes and be a Buddhist monk, but don't shave your head
Wear a cool-looking glove and rosary on one hand
Ask every pretty girl you meet to bear your child except for your girlfriend
Carry a big stick with bell-thingies on it
Use all kinds of tricks to get her to lean over you, such as pretending to die and pretending that something is dreadfully wrong with your hand.
When she leans over you for a better look, clamp a hand on her ass.
Be very adept at rubbing a girl's ass in tight, circular motions
Have a funny little ponytail
Girls:
Be very resourceful and loaded with all kinds of demon-fighting weapons
Be a kick-ass good fighter
Have a little brother under the control of someone evil
Get mad at your b/f when he hits on you but secretly like it
Get really, really, really mad at him when he hits on anyone else
Point out that he never asks you to bear his child and deny that you want him to ask
Excel at bitch-slapping and slap him for his various transgressions
Refer to him as "Lord Monk"
Ride a giant fanged cat-thing with flaming feet
Never admit to liking him, at least not until a good way into your relationship and after he's already hit you several times
Take it the wrong way when he tries to give you mouth-to-mouth because he thinks you've drowned
Point it out to him every time he's doing something even slightly perverted or racy
Know how to blush furiously, and do so when he hits on you
Don't ever hit on him
Both Boys and Girls:
Make fighting demons your life's work
Be perverse on some level so that you have even the vaguest form of similarity
....forget it the only thing you have in common is sexual attraction