What do you get a guy-friend who you like romantically for his birthday?
A date, if your both single. Ask him out.
Almost all "guy - friends" would gladly go out with someone.
What if your guyfriend who you think likes you makes fun of who you like and keeps asking you why you like him and when you say you like bad boys he tries to act bad and gets detention purposely?
Long story short, you can't. If he doesn't like you in that way, there is no way to "make" him like you. But, if you are friends with him, it is possible he will start to like you romantically. In my presonl experience, if you start paying just a little extra attention to him in your group of friends, that can sometimes help as well. Hope it helped!