How do I make my girlfriend horny? (Im not some kind of douche, and this isnt a silly question)?

You know if you are making out and in the heat of the moment, just quickly feel her up. Chances are she'll get carried away (making out makes you horny that it will only take a few buttons to go to the last base) and most likely, she won't object to it. And she'll be really wet, I'm sure.