Hmmmm, well, I can mentally crush on guys, but it can't go any further than that without hitting a brick wall really fast. I've never wanted to get real physical with a guy. GUUHHhh.
I can, however, fall for women, and I'm physically attracted to them. I don't flirt with them as often as I'm tempted too, because it's a safe assumption that plenty of them are straight, haha. I can definitely develop romantic feelings for them, and I get nervous around cute girls, whoops. There's also this really cute transgirl at my workplace, and I'm trying to figure out how to talk to her without seeming like a creeper.
Also, someone is only sexually attractive to me if I'm romantically into them first, though.
You could say I'm a lesbian.
You could also tack the "demisexual" label on to me, if you're into that sorta thing.