Cheating girlfriend has sex with sister's boyfriend at a beach house

[howjordan507]

Story is about a redhead I think, and she's going to a beach house place with her boyfriend, her sister, and her sister's boyfriend. Her boyfriend can't make it the first day due to work, so she goes with the other two, witnesses her sister give the guy a BJ and finds the other guy attractive. Later in the story she goes on a run, steps on a nail, then the sister's boyfriend helps her take it in the bathroom. That's when her boyfriend announces he arrived.

Remember the story, not sure if it was a 1 part or 2 parter, but been trying to find it for a while but no luck.