Can't find old story incest threesome.

[theonekaiser]

I can not for the life of me remember the name of a story I read a long time ago. I remember it was a guy who i think learns his father and sister are sleeping together, his father suggests he have sex with the sister, she lays on her back on a table head off the edge to suck him at one point. Eventually they have a threesome, the brother is lacking her when his dad sticks it in, he ends up locking both of them, then the father starts switching from his mouth to her pussy. Father decides to cum in the sons mouth.

Anyone know of or remember this story?