Dark Hunter 1 - Fantasy Lover by Sherrilyn Kenyon

Dear Reader,

Being trapped in a bedroom with a woman is a grand thing. Being trapped in hundreds of bedrooms over two thousand years isn't. And being cursed into a book as a love-slave for eternity can ruin even a Spartan warrior's day.

As a love slave, I know everything about women. How to touch them, how to savor them, and most of all, how to pleasure them. But when I was summoned to fulfill Grace Alexander's sexual fantasies, I found the first woman in history who saw me as a man with a tormented past. She alone bothered to take me out of the bedroom and into the world. She taught me to love again.

But I was not born to know love. I was cursed to walk eternity alone. As a general, I had long ago accepted my sentence. Yet now I have found Grace - the one thing my wounded heart cannot survive without. Sure, love can heal all wounds, but can it break a two-thousand-year-old curse?

Julian of Macedon

This book is seriously funny.

A sex slave (Julian) summoned by a sex therapist (Grace) who doesn't wanna have sex with him while at the same time cant keep her eyes (and hands) off him. Grace decides she wants to try helping Julian help the curse.

The funniest part of it was the conversation they had with Cupid (Julian's bro) in the restaurant:
Cupid: Since Alexandria caused the curse, you have to be summoned by another woman of Alexander.
Grace sat forward. "What does that mean?A woman of Alexander?"

(this is the part where you would assume that Cupid dearest would say Julian can only be set free by a woman born in Alexandria or with Alexandrian blood in her or crap like that. But no!!!)
Cupid shrugged. "Well, she has to have Alexander in her name."
"Like a surname?" she asked.
"Yes."
cue to a lightbulb moment

Grace looked up and caught Julian's tortured gaze. "Julian, my name is Grace Alexander." (ta daaa!!!)

Anyway. For the curse to be lifted Julian cannot have sex with her until the last day - something which is very hard for a sex slave to do cause he'll supposedly go insane the longer they hold out. And that folks, means they find other innovative ways to do it while not doing it while realising that they're both in love with each other and generally making this a hilarious read.