Dear gentlemen of a certain disposition:
No, lesbian does not mean she is doing it to tease and titillate you.
No, it does not mean she just needs to meet the right guy.
No, it is not the same thing as being bisexual.
In fact, there is such a gaping chasm in comprehension about what lesbians are (and aren't) that web developers have had to figure out ways how to screen out male online users who use catfishing techniques and set up fake female profiles on dating sites to hit on lesbian women.
For those that still have a hard time understanding that, here's Los Angeles–based comedian Cameron Esposito who puts it much more effectively.
Here's Esposito making her late-night debut on The Late Late Show With Craig Ferguson while Jay Leno was a guest.
In her standup, she weaves in her story about her experience of figuring out she was a lesbian. And she also manages to out Leno! (Well, sort of.)