What type of serious, personal conversations do you have when he comes to see you at work?
What you are liking, is the flirtation in his text messages but he can't seem to convey that in real life, at work when he sees you or on the "first" date you went on.. I'd say he's shyer than you think. He's capable of letting go via text messages but not so, in person.
You mention the date. But you also suggest you are not sure if it was actually a "date".. Did, he ask you actually out? Or "hang out"... It sounds as if he asked you out, tickling is cute but also shy..
Bottom line, you are not "aggressive" if you instigate rather "assertive".. Ask him to the movies and you hold his hand.. If he pulls away, then he's a friend in which case you can also say "what's wrong with holding hands with a friend?" to counter-act the situation...