That's first name Dark, last name Smile, after the the very expression on my lips right now. It's a smile, sure, but it's kinda sly; hiding something, and a trifle sinister (which is also a word for left, and I'm left-handed).
Ladies love the cool dark smile. It's just something I noticed a while ago, so I started doing it more, till it became a persona. I remember one time I followed a tour group across Cornell's ag quad, smiling darkly. And damned if one of the girls in the group didn't give me a wry, dark smile in return. That's the closest I've ever come to seeing someone else just hit it precisely. But it's definitely mine.