I wouldn't take this advice as gospel -- but is the etiquette really that different? Relationships begin when you admit to each other that you are in a relationship. At the moment you're just seeing each other, with no apparent commitment to continue. I wouldn't have thought that counts as a relationship whether you'd met online or not.
I'd suggest that if you are comfortable with it, you might want to follow boxtop's advice and take the initiative, and try to set up the next meeting yourself. It could be that he's waiting for some feedback from you, too. Then again, who initiated that kiss?
Anyway, you like him, so you might want to let him know that.