The post reactions are in general rarely used. And we wonder why. Is this a feature you don't care much about? Do you forget about it because the UI is too subtle? Or are you just missing the right reactions?
If you click on the smiley-face at the bottom right of a post, it shows you the following reactions:

These are just a few of the twemojis we now also use for the regular emojis. But what reactions would you like to see? If it's something from the twemoji set, you can find them all here:
https://twemoji-cheatsheet.vercel.app/
But we are not limited to the twemojis as long as the reaction you suggest is free to use.
Personally, I always wanted to have custom reactions for "wet panties" and "bulging pants" for arousal in the list.
And the only reactions we have avoided so far are thumbs ups or hearts, basically reactions that only express "I like this" because we don't want the post reactions to be a substitute for rating a story/chapter. Also, we don't want to include explicitly negative reactions. I don't think it would be a good idea to have a bunch of people react with vomit-emojis to a story they don't like. If somebody dislikes a story, I think it's best to either say nothing or to express that in a respectful and constructive post, not with a negative emoji.
Let me hear your thoughts and suggestions. And if somebody feels inclined to draw a "wet panties" reaction for us, I'd owe them my eternal gratitude.