Dance as just friends?

You should definitely arrive together. You should ask him to have dinner at your place and then have your parents drive you guys there. At the dance, just act how you normally act around him. As for dancing, it depends on how kids your age dance and the school rules. I dunno about freaking but do have some face to face, arms around waist, slow dances. And for the hip hop music, just stand next to him and sway side to side. Just act like you normally do.