This story was told to me by a man who discovers that his wife likes cocks much larger than his own. He relates how he learned this by watching, from hiding, as she is gangbanged while they are on vacation.
Jean, a married woman, takes her thirteen year old sister, Tricia, with her on a business trip to Atlanta. Unknown to Jean, her boss has plans for her to be a sexual gift to Japanese buyers. Tricia becomes a bonus. The Japanese pass the Sisters along to a wealthy group of handsome black men for simular reasons.
There is a small mention of bestiality but not the main story. Searching for something different a couple see an advert for slut training, and after a discussion they enquire as to what it involves, and get invited down to a farm and are shown around and rules were stated, then sent home to discuss and think it over but the wife insists they do it and arrange for her to start training.
Molly & Dan hire a pool boy who turns out to be a sexy dancer at one of Vegas' casinos. As the week goes by Molly is transfixed by his buff body and masturbates daily while watching him. Dan watches her then arranges some time for Molly to fulfill her desire, not knowing she will then take charge of his sexual activities and turn the tables on him.