I honestly cannot tell if anyone is flirting with me or not. I also cannot imagine that anyone would flirt with me in the first place, but if anyone did, I still wouldn’t know. The only flirting I knew was when my wife called me up and lectured me for not asking her out. Apparently, she had been flirting with me and I didn’t know. I am not bright.
I’ve heard an old man use it this way a long time ago in the west. You would only hear it from someone who’s very old or thinks they’re a polite cowboy.