Not sure if this is a common idea that is used, but it's something i've always tbought was cool.
I've always had the idea for this game that any Poison Type that MC fucks has a special poison that isn't harmful and instead acts like an aphrodesiac. This coukd be something cool to use if you wanna include a sex scene for a random Poison type (Since there is only 3 Poison type Legendaries/Mythicals.) and you can't think of anything for them.
TLDR: Write in that Poison Types use aphrodesiac when you feel lazy/stuck on one.