There are several “adult” extensions for Inform of various and sundry quality online. Parser/text-only AIF is not as popular as it was perhaps a decade ago. I would suggest checking out AW Freyr’s “AIF Toolkit” - although it appears it hasn’t been updated in a long time and may not work with the current Inform version. Even if it is obsolete, you could read the source text and see what is involved or mine it for useful code. I tested it for AW ages ago and all of his extensions were very thorough and well-documented.
(Note: Top level link is not porn - it is an age-gated blog with Inform Extensions to assist authoring adult/sexual games. Be aware that further links from that site may contain more specifically explicit adult and NSFW content.)