This seems such an obvious idea I would be surprised if it hadn't been thought of before. Perhaps it's because my way of thinking comes with a large side dish of kink.
Still life sessions are important for any artist who studies the human form. Erotica writers study the human form with their words. In addition to this, erotica writers explore how humans interact with each other and how their bodies react to sexual stimulation.
Imagine, then, a room in which someone was naked and masturbating, or a couple were engaging in foreplay and then sex, or a Dom was tying up and playing with a naked sub. At the periphery of the room a group of writers describing what they see on paper, having the opportunity and luxury of seeing human interaction rather than trying to imagine it.
Still life for erotica writers (although the 'life' wouldn't be that 'still'). Getting up close and studying foreplay, penetration and orgasm. Why has no one set this up yet?!