Bad sex/good sex

Confessions
- It's 6pm and I'm drinking from two different cups of coffee. Both are cold.
- I may be in love with Gary Clark Jr.
- I haven't been running in weeks.

Good vs Bad Smut
What is the line that divides good smut from bad smut? What makes it ridiculous? Weird anatomy is always a back-buttoner for me, but there are some perfectly fine smut scenes that I just cringe at sometimes and I don't even know why. And there are plenty more that I just scroll through because I'm bored out of my mind. What makes some good and some bad?

Also: What are the best and worst words to use (iyo) when referring to a female character's genitals? I really hate the word "pussy". For smut (and leaving aside issues on use outside of describing a sex organ), I'd rather go with the dreaded c-word but it's such a loaded word that I usually avoid it by not writing het. Anything's better than "unfurled blossom," I suppose.

Bad-Sex Prompting Post
What are the weirdest words, items, scenes, comments, and effects you can put into a smut scene without it descending into crack fic? I'm working on my smut-writing abilities, and I want to try this exercise. So:

Give me weird things to write standalone smut scenes around.

They will probably still end up being crack fic but that's life.