Will there be support for female on female descriptions in the future? I would imagine aggressive descriptions to be fairly easy since you can just replace {COCK} with strap-on and remove/alter cum descriptions. Consensual sex, on the other hand, would be a little more tricky, since you have to distinguish between penetrating animations and non-penetrating animations.
Additionally, there is a wish-list feature that I want to suggest. It will help you very much down the line if you wish to add new descriptions. Instead of hard-coding the text replacement variables such as {COCK} and {BOOBS}, let your JSON interpreter scan SexPart_Synonyms.txt first, record all its top-level entries and use those as text replacement variables. This way, you and your users can add additional synonyms for any other words or phrases in the descriptions.
For example, if I want synonyms for "large". I can add this entry to the SexPart_Synonyms.txt:
"large": ["large", "big", "huge", "giant", "massive"]
and then use it like:
he caresses her {LARGE} {BOOBS}.
(Also, the SexPart_Synonyms.txt should probably be renamed if this feature is implemented. Perhaps to Apropos_Synonyms.txt?)
Again, this is just a wish-list low priority suggestion, but I think it will help you and your users greatly in the future during the text content development of this mod.