Brutal Mate

One minute I'm walking back home from a nightclub. The next, I'm waking up in a cage.
Abducted by aliens. Given to an alien race. Put up for auction. But instead of being sold to the highest bidder, I'm rescued by one of the Brutal Ones: the biggest, baddest bullies in the universe.
But it's not a rescue. Not really. My rescuer makes it clear he wants something in return for saving my life...
... an Omega.
Me.