I think it's all about water. He literally washes the dirt and dust and blood of the mission off of her. Sometimes it gets all hot 'n heavy, sometimes it's more worshipful or platonic, but he literally washes the past away. Brings her back to herself. The water is scalding hot, there's maybe one candle in the room (sometimes it's almost completely dark), and he knows, he just knows when they're done by the way her breathing changes-- the way she starts to come back to herself. The spell is lifted and the princess wakes back up. (plus I have all these images of him washing her long red hair b/c clearly i need to add hair!issues to my long list of cronenburg!issues.)
Re: I SEE YOUR META AND RAISE YOU MOAR META.
... ... ...
::falls over::
*___*