I’m not 100% the year of release but I know I saw the trailer for it in the 2010s. I remember the scene taking place in a dark room or a cave. The woman, she was a more mature woman, witch like, maybe brunette/ginger and curly/wavy haired. She was seducing a young woman, I think she wanted to impregnant the young woman perhaps.
It was like the Blair witch project and the human centipede rolled into one. I feel like it could have been an independent film. The acting seemed mediocre and the gist of the trailer looked like a witch wanting to corrupt a young woman.
I remember the scene flashing as the woman spoke and there was a treen, a centipede/snake slithering on a woman’s stomach.