Daddy's Car

My step dad Andy is a car nut. He has several beautiful cars and they're all extremely well cared for.
For a while he'd let me drive one, and you guessed it, I had an accident in it.
Angry and knowing it was going to cost lots of money, he told me I was going to have to pay for the expenses of fixing it.
What money I had from my part time job he took to pay for the repairs. That was until I decided to make a deal with him.
I walked into the lounge where he was sitting alone, with my mom out shopping, and let him see me naked and horny for him.
Andy had me sucking on his cock as he tongued my pussy, within minutes of seeing me. Then fucked both my pussy and ass, telling me I was going to be his bitch from then on.
He stopped taking the money off me for the car damage and even now lets me drive another of his cars.
For that, he now fucks me whenever he wants sex, which is pretty much every day, and he insists I don't fuck anyone else.
I'm fine with that, as my step dad has such a large penis. And unlike my past boyfriends, he doesn't try to treat me like some kind of delicate flower when he fucks me.
Mom had no idea he was fucking me at first, but its been nearly eighteen months now and she's often seen her husband and I snuggling up on the sofa.
At first she'd make comments about us being to 'familiar'. But now she ignores us, even if she sees I'm stroking his cock through his comfy shorts, as I was the other day.
She's stopped short of saying it's ok for us to fuck, but mom definitely knows he's fucking me. And I figure she's ok with it.