Since it's a high school dance, most likely you'll be "freak" dancing.
Which is my favorite type of dancing to do, by the way. It's also the easiest to do. The girl's in front of you whether she's facing you or not.
So just put your arms around her, pull her as close to you as you possibly can, & move with her. Just don't let your hands wander.
If she wants you to say, put your hands on her butt, she'll take care of that.
It's pretty non-gentleman like to do that on your own.
Sorry if that's a little graphic, but honestly that's probably what you'll be doing... I just thought it'd help.