Need to Pose an Older Brother and Sister

I'm a wedding photographer and know how to put together wonderfully romantic poses. A friend asked me to do a shoot of her kids; a 20+ y/o boy and a 16 or so y/o girl.

Typically, I like the look of heads being placed very close together, but not sure how to do this appropriately for these two. Or even how to deal with hands and manage that whole physical connection that I like to try to establish in my portraits.

Any thoughts/examples?

Thanks.