Lately, I've been fantasising about using my sister in law as a freeuse sex slave.

My wife is thin and pretty, and my sister in law is quite large, but this just inspires me to be more degrading and perverted in my fantasy.

I know she is quite sexual, and so I often think of her as my personal dirty all holes fuckslut.

For example, this morning I was thinking about how I would anally train her so she was always loose and ready for me.

So, at family functions, I could slip into her room, grab her hair, pull up her dress, and shove my hard cock into her arse when ever I wanted.

So I imagined we both fake a work trip and I get a very cheap hotel.

I would tie her down on all fours and using a thick machine dildo, begin stretching her arse out.

The dildo would go in, deep, over and over, slow. Not for a few minutes, or a few hours, but all day. In and out, over and over, for hours and hours, until she is sloppy and loose and fucked out.

But I wouldn't stop then.

Maybe I would open the window, and let perverts watch for a while.

When ever I felt like it, I would fuck her throat, hard and nasty. Making her puke and gasp and cry.

And then I would cum over her puke covered face and fat udders, swinging underneath her.

All the while, that big dildo would keep sliding deep in and out, over and over, making her cum again and again and again.