Hi Razor,
I'd call this filler between assignments. You are quite a prolific writer and we instructors need to keep up, without interfering with finals that is.
OK bad endings 7, pretty good butt....
I find most human conflict, ie most stories, can come down to honest misunderstandings. You want your audience to have some sympathy for at least one character in the story and a villain often helps.
So first rewrite,
Kelly is bisexual, always has been, but maybe didn't emphasis that to Rachel.
Rachel is obsessive and possessive with a few control issues. She might have been the one who steered them into bondage. See how this changes the tone of the story. Develop the characters deftly getting the idea across to the reader through actions and conversations instead of coming right out and saying so.
Then off you go to do the project hope assignment; Once that is finished come back here review and edit this assignment, then post it here.
second rewrite will then be assigned