Can a flirtation be dangerous? Yes, sometimes.

Dr. Wendy Walsh: Flirting is not a problem for my friend. It turns me into a good listener. She and I do these spin classes together that are far past my cardio ability. During my near-heaving pants, my friend loves to recount her latest flirtation story. The guy is either an online friend whom she knew in a prior life, or someone she just met on Facebook. Sometimes it's another father at her kids' school with whom she's been locking eyes in the real world, often during afternoon pick-up. Now, the thing you should know about my friend is that she is married. And, she never, ever would have an affair. This I can assure you. Her marriage is as stable as a rock. She loves her husband a ton.

So, what's all this flirting about?

I ask her this after class as I attempt to rub a mascara ring from under my eyes. She tells me it's harmless. It's a little charge. Then she whispers this one thing, and I finally get it. "Ya know," she smiles, "it actually helps me make better love to my husband."

Psychologists and sex therapists have long known that one secret to long-term hot monogamy is an active fantasy life. Men, who are far more visually stimulated than women, may need porn, but we chicks just need a sly glance from a gamely male and our wheels of invention start to spin like wild in our minds. And let's face it, ladies -- sexual attraction sometimes wanes as the years go by and our partner's once exciting nouveau pheromones become a somewhat tired, familiar background odor in our daily lives. We all yearn for a little excitement, and the wearying business of marriage and kid training is sometimes -- well, sometimes, it is anything but exciting.

But can a flirtation be dangerous? Yes, sometimes. There are two instances where I think a little smile and wink can amount to playing with fire. The first is if you have a belief system where thoughts can be sins, and therefore the thoughts are followed by painful feelings of guilt and shame. If your religious conditioning plays negatively on your self-esteem and you feel bad for having such "unpurely fun" thoughts, then these kinds of extramarital flirtations are not for you.

More likely in today's culture is the other risk: Poor boundaries. If you are the type of person who can't keep your fantasy life in a jar with a lid, then you are at clear risk for breaking your marital vows. Fantasies are meant to be just that -- a complete fabrication. A product of your imagination. That little jar of excitement can be opened and screened like a movie whenever you are romping with your mate, but if you find yourself wondering what it would really, for real, be like with this dude, then you need to stop yourself, girlfriend.

Here's my advice if you are a novice at this game: Decide where the boundary is. A phone call? A text? A quick brush of each other's bodies as you dash across the crowded schoolyard? You decide. But when that boundary gets reached, you have to cut it off. Decide well before you have a target. Then stick to your guns. There is much at stake here. And a good man's heart hangs in the balance. But non-contact smirks and hair flips are all part of the game. Go for it, mama. Just make sure you bring it home to daddy.

Dr. Wendy Walsh holds a Ph.D. in Clinical Psychology and her area of interest is Attachment Theory, a psychological, evolutionary and ethological theory that provides a descriptive and explanatory framework for understanding interpersonal relationships between human beings. As a psychological assistant registered with the California Board of Psychology, Dr. Walsh has treated individuals, couples and families for a variety of mental health concerns including personality disorders, anger management, eating and substance disorders, and depression. Connect with Dr. Walsh on Facebook.