Colder Than Fiction by Amanda Meuwissen

An author is often haunted by their muse, but this one promises a kiss.
Ezra wakes with the worst hangover of his life after a Christmas party he never wanted to attend. It’s the holidays, he was just dumped by his boyfriend, and his next manuscript is due to his publisher by the end of the year, but all Ezra wants is escape. Then escape finds him when the antagonist from his current work in progress appears in the flesh to help him finish his book – and indulge in everything else that’s been missing from Ezra’s life.