Ok, I've had a crush on one of my guy friends for a long time now. About a week ago, our mutual friend pulled me aside when he was out of the room and said that she thinks that he likes me. Of course, being the shy dumbass that I am, my reply was "Oh, he does?" Well, now I kind of want to ask him about it personally, but I have no idea how I should bring it up. ;_; Should I just ask him about it directly?

No. Don't do anything. Just do nothing and be tormented by your regret for years to come, everything will work out much better for both of you that way.