The perfect come-on. It’s the Holy Grail of dating, the enchanted key that unlocks the glorious gates of Eternal, On-Demand Lady Lovin’. Many seek it. Many fail.

“Shoot, I seem to have lost my phone number. Can I have yours?”

“If I could rearrange the alphabet, I’d put U and I together.”

“Did you clean your pants with Windex? Because I can practically see myself in them.”

The notion that a single pick-up line could win a woman’s heart, or even convince her to doff her Hanky Pankies for an exceedingly pleasant 37 minutes, is so far-fetched I’d swear it were a myth. Except that, occasionally, it works.

I was sitting outside a Denny’s recently, waiting for my family to arrive. A couple of young guys were walking in when one stopped and said, “Excuse me?”

I turned, expecting him to say that I’d dropped my car keys. Or forgotten to put on pants. You know, the usual.

“I just want to tell you, I think you’re really pretty,” he said.

And that was it. No creepy alligator smile. No goofy drunk-on-the-dance-floor body language. Just “you’re really pretty,” a shy grin, and he moseyed into the eatery.

I’ll be honest. If I had been single, I would have followed that fella inside, slid into his oversized booth, and ordered up his Moons Over My Hammy, if you know what I mean. (No, I don’t, either, but I would have figured it out, I assure you.)

As it is, his comment made my day, which is a little bit embarrassing. And a little bit confusing. How is it that a wolf whistle can make a gal feel cheap, vulnerable, and somehow guilty (“I KNEW I shouldn’t have worn this dress downtown”), but an artless compliment can leave her girlishly giddy.

I feel for guys, I do. It’s not easy trying to charm a woman. You work up the courage to make a move, heed your instincts, seize the moment, and — like the tollbooth worker who called my friend “babe” and touched her palm as he gave her change — all you get is an “eww! yucky!” in return. And what works with one gal may not work with another. Some swoon for one-liners like, “Did the sun come out or did you just smile at me?” whereas such a string of words might cause me to vomit violently.

I do have a weakness for funny. My friend Chris says his best line is, “Can I buy you six drinks?” Who wouldn’t let him buy her at least the one?

My girlfriends say the best come-ons are respectful, authentic, and precisely tailored to the recipient. Also, this works well: “Hi.”

But here’s a little secret. The real reason my pancake-pursuing suitor (let’s call him Denny) made me beam rather than cringe is that he walked away. Perhaps he got a closer look and realized I was old enough to be his, um, aunt. His obscenely cool and unreasonably gorgeous aunt. Or perhaps he spotted the glob of lime-green Play-Doh in my hair. Whatever.

What mattered, from my perspective, was that his flattery had no purpose other than to make me feel good. And that’s the key to the charming come-on, guys. It must be uttered not with the intent of scoring, but with the sole purpose of making her happy. The great irony, of course, is that if you genuinely mean it — if her feelings are your first priority — then you’re worthy of her and you’ll hit a home run.

Or a Grand Slam, if you’re at Denny’s.