Gonna kill him

"Mother fucker," Erin swore as she tried to stuff some stranger's enormous new breasts back into a bra that was now way too small for them. Fortunately, she was cleaning up the hotel room alone. No telling what would have happened if one of her fellow maids had been in there with her and seen her tits suddenly balloon to gigantic proportions.
Erin regretted giving her boyfriend access to the body part swap device. Now Erin had some stranger's massive tits hanging from her chest. Somewhere out there a formerly big breasted woman was getting the shock of her life.
The body part swap device had been fun at first, and Erin and her boyfriend had used it on each other, experimenting with different combinations in a night of interesting and exciting sex.
But Erin's boyfriend had kept control of the device with her body logged in, and had been swapping out various parts all day while she was at work. In the morning it had been her ass, which had suddenly expanded beneath the maid uniform into a plump, round pinchable butt. Then her fingernails, the ragged edges replaced with impeccably manicured curves. 
Those changes had been much easier to hide than the breasts. In the end she had to ditch her bra, stuff her tits into her uniform, and yank up the zipper. Even then it was a tight fit. She was going to kill her boyfriend for this when she got home. And she wondered if he would even recognize her.

A goddess offers to give her power to a rich man if he can survive being switched into the body of a beautiful young woman in an impoverished country for two weeks in Gods and Men (Part 1), available on Smashwords or Amazon. Preview here.