Spanking my Wife's Sisters by Rosie Hynds

It was Jessica who insisted the bet was made. It was stupid and a marriage wrecker all rolled into one. To spank one of her five sisters would have been silly, but all of them in thirty days? That was the challenge and one which would test a marriage to the limit. Then came the twist, two of them had to be bare, with husband Mark having to chastise naked flesh. It was dumb to accept, but once he had, he was faced with no option but to attempt to bring her five sisters to hand.

The stakes were high. Her bottom was on the line and the right for Mark to finally claim it for the first time. Failure was impossible to contemplate, his eager brother ready to step into the marital bed as her reward, with a wife only too ready to inflict the ultimate humiliation.

Thirty days is all Mark has and as soon as the bet is made the clock is ticking, with five less than willing sisters all out there waiting to be spanked.