YOU'VE ALWAYS PRIDED YOURSELF ON BEING ONE OF THE NICE ONES. YOU HOLD OPEN THE door, compliment her mom, even let her eat off your plate. What happens? She takes off with your best friend. Vowing to be an asshole isn't the solution. Instead, take these cues on how to be a badass and still be yourself.

RULE 1

Make her think she can be the one to tame you

She wants you to be the beast she reined in. Your goal: Make lots of comments referencing the girls who were never able to get you to settle down before she came along. She'll pride herself on being the one and only (for now).

RULE 2

Defend her honor

"Women want security, even if it's just a sense of security," says Robyn DeVal, Ph.D., a sex therapist in Tampa, Fla. "It goes back to our animal roots." Since there are no carnivorous dinosaurs to defend her against, offering to dismember her demeaning boss will often suffice.

RULE 3

Keep your poker night with the guys

She'd prefer to think that you make time to spend with her and not that you're just at home watching Cops and sitting by the phone. NOTE: Having friends and outside interests makes you intriguing.

RULE 4

Take control

Make sure she's taken care of, without her asking, and without waiting for a thank-you. Whether it's picking her up from work or ensuring that she always has a drink in hand, letting her feel as if she's queen of your little empire can be intoxicating. After all, power is the ultimate aphrodisiac--even if it's just an illusion.

RULE 5

Nurture her naughty side

She's spent her whole life being told to be nice, cross her legs, smile, and be polite. Somewhere inside there's a wild animal yearning to be unleashed. Make her feel that just by being with you, she's "bad" by association--comment on her feistiness, her sexy strut, and her risque sense of humor.

RULE 6

Predictability is overrated

Mix things up a little. "Keeping that spark from week to week takes a little work and imagination," says Ian Kerner, Ph.D., author of She Comes First. "It's easy to get lazy in relationships, but it leads to trouble." NOTE: Being unpredictable doesn't mean not calling her when you said you would--that's not being bad; that's just being a jerk.

RULE 7

Show her off