Flirting's fun until it crosses that "but I KNOW you don't mean to be so standoffish" line, assuming that enough persistence and, uh, "sweet-talking" will eventually wear down an ice-queen's resistance and warm embraces will, of course, follow. Uh,no. If someone is inching away from you, physically or verbally, the correct response is not to keep following in the hope that somehow somewhere you might find a gap in the obvious fence and slip through into a territory access to which is not willingly given. THAT'S when it crosses into harassment. That implicit smirking knowledge by the harasser that resistance WILL crumble, by God, or else - because he's so irresistibly cute or something, I don't know.
That's the tactic used by my super-cute sweet now lost and much missed cat who never really grew up beyond being a kitten and whose only defense against misdemeanours he was caught in was a head-to-the-side-blink-blink-blink thing that said, "But I'm so CUTE! How could you possibly be mad at me?" Yeah, no, it didn't always work THERE, either. And trust me, he was a lot cuter than any wannabe Romeo who won't take no for an answer could possibly be.