I know she isn't explicitly tagged in this, but I like imagining this unidentified slave in the nun costume as being LC's Allison who's riding her mistress' cock/strap-on. Their face looks like hers, anyhow. This could be an independent side-story for Allison that deviates from the canon direction of LC's current timeline where as part of the project of breaking her after her forced gen-swap, her mistress sent her to a convent where she was to receive intensive training and intimate guidance on how to conduct herself properly in her newfound role