The Nightmare Before Kissmas by Sara Raasch

Red, White & Royal Blue meets The Nightmare Before Christmas in a sexy, quirky rom-com where the golden-hearted Prince of Christmas falls for the totally off-limits Prince of Halloween.

Nicholas “Coal” Claus used to love Christmas. Until his father, the reigning Santa, turned the holiday into a PR façade. Coal will do anything to escape the spectacle, including getting tangled in a drunken, supremely hot make-out session with a beautiful man behind a seedy bar one night.
But the heir to Christmas is soon commanded to do his duty: he will marry his best friend, Iris, the Easter Princess and his brother’s not-so-secret crush. A situation that has disaster written all over it.
Things go from bad to worse when a rival arrives to challenge Coal for the princess’s hand…and Coal comes face-to-face with his mysterious behind-the-bar hottie: Hex, the Prince of Halloween.

It’s a fake competition between two holiday princes who can’t keep their hands off each other over a marriage of convenience that no one wants. And it all leads to one of the sweetest, sexiest, messiest, most delightfully unforgettable love stories of the year.