"The Jerinah? Well, it's kind of a bit odd, but you have to understand that the Atreides, like most people hereabouts, are Spelljamming world-travellers at heart, yes? Well, they are of the mind that any of their prospective scions would be unfit to rule if they just stuck around the palace all day, naive and oblivious to the outside world, so they go on a coming-of-age ceremony called the Jerinah that they must complete before they get married and settle down, where they visit many different worlds. Supposedly, it helps them learn about different cultures, make connections in many different places, and all that kind of stuff."