Sodomise the Slut

"I want to fuck you in your tight little ass!"
"Ohh Billy, in my ass? I've never done that before, normally people just want to piss on me, or me to piss or shit on them or something like that. I don't want to do anal".
"Well Stacey you little slut, bend over and show me your rusty sheriffs badge!" Billy exclaimed. "I don't care what you like or don't like, this is all about me paying you money to be my bitch!"
Stacey could see a wild look in Billy's eyes, and decided to save herself a smack in the face, and do what Billy wanted, she was, after all, a dirty little slut. Walking over to the bed in the room, she slowly bent from the waist, until her chest was touching the bed. She reached behind her, and slowly worked up her tight micro mini skirt up over the rest of her butt (it was that short, it didn't really cover much up anyway).
"That's a good little slut, now reach behind yourself, grasp a butt cheek in each hand, and pull them apart so I can look at you little brown eye" said Billy, lovingly looking at her tight, white, taut buttocks.
Stacey did as she was told, starting to like the depravity of her situation.
Billy watched her do this, his erection standing proudly in front of him.
Now, a little more about Billy. For an eighteen year old virgin, he was pretty well off. Far from being a weedy little geek, he was actually a pretty big guy, tipping the scales at 124kg, and standing at 6' 4". He wasn't fat by any means, but he wasn't very cut either, just solid. He had a penis to proud of. When erect, it measured 11 inches long, but the girth, what girth. He came in with a circumference of 7 inches around (the size of an average mans forearm), being about 2 1/2" at the widest point, which was the head of his cock.
"So Stacey, are you saying that you've never been fucked up the arse before?" he asked.
"Only once, by my father, just before he sold me to this whorehouse. I didn't like it one little bit. He was so big, and it ripped my poor little hole to bits."
"So, he was pretty big was he. Bigger than me?"
Stacey looked around at Billy's cock and immediately turned to run away "It's huge, I can't fuck that. It would kill me".
Now, Billy may be a big man, but he wasn't slow, even if Stacey was only a 48kg, 5'5" girl, he could still move faster than her. Grabbing one of her wrists with one hand, the other grabbing her waist, he stopped her short quest for freedom. Moving his hand off her wrist, he grabbed the other side of her waist. His huge hands easily encircled her tiny waist.
"Now look here you uppity little bitch" he roared at her. "I paid good money to fuck you in your arse, and I'm getting my moneys worth!"
"But your far too big. I don't think that would even fit in my pussy, let alone up my bum!" Stacey cried, shrinking away from Billy's grasp. "I know you've paid alot of money, but... can we do something else. You can piss or shit all over me, even in my mouth, just please, don't fuck my bum" Stacey pleaded with the man towering over her, still clutching her waist.
"I will fuck you in ass, but... you've tempted me to be nicer to you than I was going to be. I did not expect someone so anally inexperienced. I was just going to shove it in dry, and fuck you hard and fast, until I coated, what would no doubt be, a very bloody arse full of my cum. But now I'm not so sure, perhaps I could use some lube, maybe even stretch you with my fingers and tounge first to make it more pleasurable for you. But then again, we are here for my pleasure, not yours."

What to do???