Going from Casual to Relationship

I have recently downloaded Tinder trying to meet new people, since I'm not really good at the whole going-out-and-flirting-with-a-complete-stranger-right-away. It's a bit easier since you can see if you have similar interests, and if you think you'd be able to hold a conversation. I matched with a guy who started talking to me, and we agreed that we'd actually enjoy a hook up. I invited him over, honestly against my better judgement- I know- and we talked for about two hours and had a couple of drinks before we had sex. He actually ended up getting "Whiskey Dick".. But we laughed and talked for a while before he went home. The other night he came over and we spent some time together again before we had sex, and then talked some more. The only thing is: I seem to like him more than just for a hook up. I'm just not sure on how to go to the transition, and honestly afraid of scaring him off. Any suggestions?