It would only be weird if you straight up asked him over FB IMO. I think you can go about it two ways: 1. You mention the dining hall and not being able to talk to him, then ask if he wants to hang out 2. Start a conversation and see how he responds, then go for it... Both ways, however, kinda put him on the spot and possibly ghost, but I hope college students are more mature than that, lol. Take my situation, I'm trying to ask a girl out who is not in my grade in HS, and the only time I get to see her is either during filming with 4 or 5 other students, or a ride to filming, which was only once and only the two of us. Well filming is ending soon and I've been trying to give her another ride b4 the last one and it's not looking likely. As much as I want to text her and ask her, the text conversations haven't been very exciting, so I know she will 100% ghost me. I suggest option 2 because it allows you to "read the room" and see how he might possibly feel. Also, since this will probably be done over text, I want to say ask him to grab coffee first. Good luck!