Maybe a shot of her at butt depth, all muddy, with the camera behind her, as she looks back at the viewer with a smile, hands on the surface of the mud (or if you want, a gesture akin to inviting the viewer to join her)
"Something like this?" Victoria asked, as she tried to put on a seductive expression. She'd lost count of how many times she had been asked to model various poses while sinking in this quicksand pit, but she was becoming more and more comfortable; whether it was peril or pleasure, the experience of feeling her body slowly sinking deeper and deeper in the muck was undeniably exciting.
"Wanna join me?"
I've also been creating quite a fair bit of backstory for Victoria and some of the other characters I've featured so far, so hopefully you'll be reading about Victoria's sinking experiences in upcoming tales.