Shining Armor had only just wed with Princess Mi Amore Cadenza–For reals this time– and they had had a wonderful honeymoon together. They had returned to the palace of Canterlot, not having a place of their own, to discover that Her highness Princess Celestia Del Sol wanted to bring back an old tradition written into law.

She won't go into details, but it's a little close. Very close. Probably borderline intimate.

To put it bluntly, Celestia wants shining armor in her bed.

Still, nopony except for Shining really cares; it's just not that big a deal.

(Regrettably inspired by the royal tradition where a king got to "try out" the new female in the royal family before her husband did.)