Bad at flirting

How do you hint to a guy you want to have sex with him..I'm in college and there's this guy in one of my classes I'm attracted to but I don't know if he likes me or not. He says hi to me every day and smiles at me but he may just be a friendly person by nature. I want to ask him for his Snapchat but would that be too obvious? I'm also afraid of rejection and it would be awkward if he doesn't want to and I have to see him everyday. :/ And yes I just want sex not a relationship because just got out of a relationship a month ago and I'm not looking for another one this soon.