How Do I Ask Out A Hookup?

So there's this guy I've hooked up with a couple times. I will admit that I don't know him very well, but I like him. If nothing else, I'd like to become better acquainted with the guy that I'm screwing. 😂 However, he is a very reserved individual. He doesn't offer any information about himself or provide anything beyond the necessary details. I don't even know his last name. At this point he is literally just a guy I've had some fun with, but whom I would like to get to know better. I'd like to ask him out to dinner, but he's never shown the slightest hint he'd be interested in anything other than sex. Should I just forget about it?