One Last Fling by Jason Hytes

Joanne was only eighteen, but she had the sexual desires of three full women. Now that she was about to be properly married she could feel the suffocating walls of respectability closing in on her. She had to have one last fling, even if for only a week end-one wicked, wanton week end on the town.
This is the story of Joanne's week end, and of how she thought she had found the one man who could fill her sexual demands-then, only to meet his sister who showed her a new and different means of satisfaction.

'She thrust herself against him, carefully, slowly, grinding her hips.'