If you're not a botanist, X-ray technician, geometry student, or science fiction writer, you don't use many X-words.
Unless X-rated is your genre. I took a class recently that defined the difference between erotica and X-rated erotic romance.
In erotica, sex is the plot. The lovers meet, they have sex. The story sets up for another round of lovemaking or ends.
In erotic romance, sex forwards the plot. The lovers meet. The plot throws them together until they end up in bed. They have a great time, but character conflicts come up and they split up. Their attraction is so strong that they hook up again despite the issues that presently (and for the foreseeable future will) drive a wedge between them. The plot evolves so they find ways to overcome their external issues--or they grow emotionally. They resolve their issue(s) and reach the HEA/HFN.
The degree of heat (amount of description) of the lovemaking acts determines whether a romance is erotic or sensual or sweet.