Sadly, I can't remember if it was in English or in German, but the odds on it being in English are pretty good.
It was about a woman with her husband, daughter and their dog visiting a family consisting of at least two brothers and their mother to do all kinds of kinky shit, and at the end the dog bites into the first woman's breasts.
It also might have been from another site originally, as it wasn't in the usual story style for GC.
If anyone knows what I'm talking about, a link (or repost) would be much appreciated.