Chrissy is cheating on Jason with Eddie. Eddie really likes the idea of getting Jasons sloppy seconds, so when Chrissy comes over from Jasons, he makes her sit on his face and push out Jason's load. He fingers and licks Jasons come out of her and when she's clean he fucks her full of his come.

Chrissy and Eddie are really into it, up to the author if Jason knows/likes it/whatever.